View Full Version : BCM Lower not compatible with PMAG Gen3
In case anyone else wasn't aware of this. I wasn't.
Apparently not all BCM lowers are compatible with M3 PMAGs. I just completed a build using a BCM lower. When I took it to the Range I realized that I could not fully seat any of the Gen3 PMAGs I brought. The issue is that this version of the PMAG has a tab on the spine of the mag to prevent over insertion. On this lower that tab prevents the mag from being fully inserted.
I e-mailed BCM about it, and their response was that this sometimes happens with their lowers, and I should only use mil-spec mags with their "mil-spec" lowers. They claimed that there are no tight controls on this area of the lower.
The issue that I take with their answer is that M3 PMAGs are mil-spec in that they have been issued an NSN (1005-01-615-5169) and are approved by the Army and the Marine Corps. In fact the mags I was using were issued to me, and are what all my teammates use in our Colt M4s with no issue. I have also never had issue using these mags with my DD rifles or guns built on Spike's lowers.
Live and learn. I'll stick to Colt and Daniel Defense, or even Spikes lowers when I want to build something.
I have a Noveske with the same problem.
But I have a cheapo range toy poly lower that doesn't... Go figure.
I am surprised with the BCM response though.
The M3 PMAGs have problems with lots of different weapons. But they seem to be great for their intended role.
Sent from my Pixel 2 using Tapatalk
The issue that I take with their answer is that M3 PMAGs are mil-spec in that they have been issued an NSN (1005-01-615-5169) and are approved by the Army and the Marine Corps.
Being MIL-SPEC and being issued are two different things.
PMAGS are not MILSPEC nor are they STANAG 4179 compliant.
Perhaps I should not have claimed the PMAGS to be mil-spec. I'm not prepared to argue what constitutes mil-spec or not. Regardless they are approved by the USA and USMC, which indicates a certain level functional testing with mil-spec weapons.
The purpose of this thread was really to make people aware of an existing issue.
*Edited to be more cordial.
Looking at MagPul's description of their M3 mags it states "the GEN M3 is optimized for Colt-spec AR15/M4 platforms".
Colt-spec is apparently now a thing.
I will stick with Colt and Daniel Defense from now on.
I'm not going to sign up for photobucket.com just to post pictures, but there is a discernable difference between my DD lowers and this BCM.
The DD lowers are flush with the trigger guard at the magwell. The BCM magwell extends a fraction of an inch below the trigger guard.
There is no wearing in of these mags to fit. Also, I have already run thousands of rounds through these mags in my work gun.
I have a KAC lower that does not accept NHMTG mags, but works with every p-mag I own.
jethroUSMC
03-15-18, 17:29
Also the M3 magazines state that they sometimes need to be worn in a bit to fit all lowers. It took more than a few times inserting and removing the mags probably several minutes per mag until they fit in all of my lowers.
Beat Trash had the same problem a few years ago.
https://www.m4carbine.net/archive/index.php/t-169913.html
I have 2 BCM lowers and I use M3 PMAGs exclusively and have had 0 issues.
My BCM has never had a problem with any of my Gen M3 PMAGs, but I'm aware of the issue. At one time I read the entire thread on here about it, and I really wasn't impressed with BCM's attitude toward the issue. The mil-spec excuse is pretty lame when Colts don't seem to suffer the same problem.
Guys,
This is a known issue.
BCM has known about it for a few years and has done nothing about it. They blame MagPul and say there is nothing in the TDP as the length of the magwell where the over insertion tab hits.
If you ask MagPul then they blame BCM for out of spec lowers.
Basically you have four choices
1. Sell lower
2. Use different mags
3. File off tab on mags
4. File bottom of mag well on lower
dang glad my gen3 work. Is it possible that some g3 pmags work and others do not? should I be cautious going forward?
dang glad my gen3 work. Is it possible that some g3 pmags work and others do not? should I be cautious going forward?
Yes. And probably not.
I’m sure the specs on the pmags have more tolerance than the lower. Out of all the lowers BCM puts out I’ve only heard of this a handful of times so it’s a small percentage. But what gets me is BCM won’t do anything about it. They should machine the back of the magwell to properly length on the forged lowers that are a little off.
I’m glad all my BCM lowers work with gen3 mags or I would be pissed. And the OP should be rightly so. I think BCM is held to a high standard here and they fall short on this one.
I have a KAC like that that I refuse to build out and no one will buy off me for far less than I paid. I have plenty of high end lowers that have no issue with gen 3 pmags. It's tolerance stacking and in my opinion is BS.
My rifles have to accept P-Mags.
I don't think there is an issue of tolerance stacking. As previously stated the Army and USMC approved the M3 PMAGs for combat use after thorough testing. I don't want to talk out of my ass, but I'm sure that potential tolerance stacking issues would be identified. There's no way they would approve a mag that would fail to function in a percentage of their weapons.
I tried 7-8 M3 PMAGs in the lower in question. They all failed. This lower is clearly off. On all my other rifles the magwell is even with the trigger guard. On the BCM lower the magwell extends below the trigger guard. I don't want to be a crybaby, but I am dissapointed. Something either meets the standard or it doesn't. This item clearly doesn't meet the standard.
I'll probably either sell this lower or put it on my beater gun.
See the picture below. I should add both trigger guards are the same design. The only difference is the logo on them.
51043
Diamondback
03-16-18, 00:24
Hell, M3s rack in my cheap crappy plastic 80%s... you know there's something SERIOUSLY wrong when my $25 Bubbafied homebrew EP Armory plasticrap works and your expensive BCM doesn't.
Not to diss BCM, the parts I've bought from them I've been impressed with and I'm thinking about asking them if they can do an unassembled "kit" version of their C8 URG for the GF... but there's just something head-scratchingly "WTF?!" with them on this one.
We live in a P-Mag world, so my lowers, whatever the brand, have to accept unmodified P-Mags.
Agreed. I love BCM, but was somewhat disappointed by their response to the issue a while ago.
Sent from my iPhone using Tapatalk
This is the first I've heard of this, and I have quite a few BCM lowers (and quite a few gen 3 PMAGS). I'll have to grab an empty PMAG and try all my lowers.
I have a KAC like that that I refuse to build out and no one will buy off me for far less than I paid. I have plenty of high end lowers that have no issue with gen 3 pmags. It's tolerance stacking and in my opinion is BS.
I’ll give you $100 for it.
dreadpirateroberts
03-16-18, 07:21
My BCM lower accepts gen 3 pmags just fine. Also bought it a while back, maybe its the new stuff?
I’ll give you $100 for it.
$101 and I’ll split the shipping. :-D
I just want to reiterate. This is not an issue on all of their lowers.
It is a defect from the forging, and it's not a dimension that is checked as part of BCM's quality control. They don't consider it to be important. According to customer service that area is not well defined within the milspec they reference.
Perhaps, that is why Magpul states that their M3 mags are optimized for "Colt-spec" AR15s and M4s.
By the way I replied to customer service that if they considered this to be normal and within their acceptable tolerances that they shouldn't mind if I post about it online.
I just want to reiterate. This is not an issue on all of their lowers.
It is a defect from the forging, and it's not a dimension that is checked as part of BCM's quality control. They don't consider it to be important. According to customer service that area is not well defined within the milspec they reference.
Perhaps, that is why Magpul states that their M3 mags are optimized for "Colt-spec" AR15s and M4s.
This is true. It is a very small chance that your lower will not work with a gen3 pmag.
But I think BCM should take care of those few customers that are having problems.
Doc Safari
03-16-18, 09:12
I am a BCM fanboy. They are technically correct that their lowers are made to work with milspec (i.e. aluminum GI ) mags.
Having said that, we do live in a MagPul world, and if I ever get the desire to "thin the herd" the BCM's will be the first out the door. We know the Colts work with all quality mags, and that's just another reason to buy Colt. No matter if BCM makes a top tier weapon and the quality is equal to Colt, that one little issue is too much of an "if" in a situation where you might not have a choice of mags in a SHTF situation.
I don't think there is an issue of tolerance stacking. As previously stated the Army and USMC approved the M3 PMAGs for combat use after thorough testing. I don't want to talk out of my ass, but I'm sure that potential tolerance stacking issues would be identified. There's no way they would approve a mag that would fail to function in a percentage of their weapons.
With KAC it is. Their are KAC lowers that have no issue with Gen 3 pmags and others that do. This means the magwell dimensions are different.
I am a BCM fanboy. They are technically correct that their lowers are made to work with milspec (i.e. aluminum GI ) mags.
Having said that, we do live in a MagPul world, and if I ever get the desire to "thin the herd" the BCM's will be the first out the door. We know the Colts work with all quality mags, and that's just another reason to buy Colt. No matter if BCM makes a top tier weapon and the quality is equal to Colt, that one little issue is too much of an "if" in a situation where you might not have a choice of mags in a SHTF situation.
Completely agree with this!
According to customer service that area is not well defined within the milspec they reference.
And none of the blame goes to the company that used a not well defined dimension as an index point?
It's a huge problem with many aftermarket parts, where someone goes out and measures a few parts and then assumes that is the nominal size. Not knowing the actual dimension, the actual tolerance, and some do not even know what nominal means.
Magpul should release a print with an added dimension and tolerance that the magazine was designed to function with. Lower manufacturers can choose to add that to their process and advertise it as compatible.
SomeOtherGuy
03-16-18, 10:34
And none of the blame goes to the company that used a not well defined dimension as an index point?
***
Magpul should release a print with an added dimension and tolerance that the magazine was designed to function with. Lower manufacturers can choose to add that to their process and advertise it as compatible.
I agree, and like this idea. I love Magpul products generally and am using M3 Pmags, but I think the overtravel stop tab is unnecessary and not a great idea, for the reasons described here. It also doesn't work with Noveske gen2 lowers, and probably various others. While it's probably the most reliable magazine available for lowers it will fit (based on the published military test results), having to go and check the mags for fit with every lower you own is a hassle, and a hassle that didn't generally exist with earlier gen Pmags.
Rayrevolver
03-16-18, 11:23
It also doesn't work with Noveske gen2 lowers, and probably various others.
To be clear, early Gen 2 Noveske lowers had issues. At some serial number going forward they are compatible.
I took a dremel to my SBR early Noveske Gen 2 lower so I could run the D60. Is what it is.
I have a later Gen 2 that has the wider cutout at the rear of the magwell.
To be clear, early Gen 2 Noveske lowers had issues. At some serial number going forward they are compatible.
I took a dremel to my SBR early Noveske Gen 2 lower so I could run the D60. Is what it is.
I have a later Gen 2 that has the wider cutout at the rear of the magwell.
Yeah but Noveske lowers have always been too tight. I had a Gen II and now have a newer production Gen I. The only mags that will drop free are standard aluminum and M3s, though they’re still very picky. I’ve had aluminum mags fail to drop free just because the gun wasn’t completely parallel.
Sent from my iPhone using Tapatalk
I never understood a point of overtravel stop in Magpul mags. I'm not aware of any original military magazines in the world which have that. I think that if you rely on over travel stop in order for your mag to work you have a design issue with the weapon.
BravoCompanyUSA
03-16-18, 13:46
The M3 version of the PMag adds an “over insertion tab” on the rear spine of the magazine. Unfortunately, it interfaces with an area of the lower that can vary substantially during the manufacturing of a milspec lower receiver group.
For this section of the weapon you have 2 sets of tolerances; forging tolerances and machining tolerances. When you add them up the Mil-Std TDP finished product has a range. For over 5 decades, the dimensions controlling the lower end of the magwell have been generous with tolerances. Allowing as much as +-.060” of tolerance in the M16, and even more within the M4 requirements, with the majority of the tolerances in the forging. That means lowers can vary by 1/8” in this area!
BCM lower receivers are built within the semi auto versions of those prints. Any AR15 lower built to the correct print could still have this issue with the over insertion tab.
It is not fully backwards compatible. Based on our analysis, the location of the tab is based on a lower built to the center of the tolerance range, which leaves the possibility of up to 1/16” of interference in some cases. We have gone over the documents many times to ensure this is not an oversight on our part. If it was, we would scramble to make it right. We have not found this to be the case though. Due to the allowable tolerances in the mil-spec prints, the tab will work with some lowers of any manufacturer, and not in others of any manufacturer. This is not specific to BCM and similar situations will arise from many other makers whose tolerances may even exceed the TDP allowances.
The PMag is obviously an excellent design, but this tab has the possibility to cause issues with any milspec lower. As a result it is possible even within the same manufacturer to have it fit some and not on others. If you want an inventory or load out of fully cross compatible mags we recommend you file off just a bit of that tab, because while it may fit in the couple of your lowers, and then it may not fit in the next couple of your buddies AR.
http://img.photobucket.com/albums/v445/bravocompanyusa/lower%20magwell_zpsa2e5orek.png
Thanks for reading,
Hope this info helps.
Doc Safari
03-16-18, 13:52
In support of your position, Bravo Company, I just finished reading this a few minutes ago:
http://www.thefirearmblog.com/blog/2016/07/20/why-i-dont-use-pmags/
PMags are problematic in several different rifles, not just BCM, and not just AR's.
My take: I'm rethinking this; it's not a BCM problem. I think MagPul is in denial about just how compatible their mags really are. I'm going to go out on a limb and say that the over-insertion tab is a bandaid solution to a design that is not perfect.
Seen here is a few examples of when a PMAG has to be manually removed: a problem that isn’t present most of the time with plain old aluminum magazines.
Next up is damage to the SCAR.
Using PMAGs can actually do irreparable damage to an FN SCAR rifle.
The mags cause the bolt catch to rise ever so slightly and drag on the bolt lugs, which results in significant damage over time.
PMAGs are pretty notorious for not wanting to work in various platforms, including guns like the HK-416 and M27-IAR.
Note here that this PMAG will not insert into this civilian version of the HK-416, due to the odd body geometry.
Also, PMAGs had trouble fitting in firearms like the British SA-80/L-85, and will not fit in the FN FS-2000 without the user modifying the weapon by removing a component that serves to seal the weapon from dirt and debris.
To my knowledge, no PMAGs will work in the FS-2000 to this day without modification.
"The Magpul GenM3 PMag was the only magazine to perform to acceptable levels across all combinations of Marine Corps 5.56mm rifles and ammunition during testing. That magazine has, therefore, been approved for use for both training and combat," Marine Corps Systems Command (MARCORSYSCOM)"
"GENTEXT/RMKS/1. PURPOSE. THIS MESSAGE PROVIDES UPDATED GUIDANCE REGARDING THE USE OF MAGAZINES FOR THE M4/M16 SERIES AND M27 INFANTRY AUTOMATIC RIFLE (IAR). 2. BACKGROUND. MARINE CORPS UNITS WILL NO LONGER RECEIVE THE LEGACY MAGAZINE WHEN ORDERING NATIONAL STOCK NUMBER (NSN) 1005-01-561-7200; THIS NSN WILL DEFAULT TO THE U.S. ARMY ENHANCED PERFORMANCE MAGAZINE (EPM), NSN 1005-01- 630-9508. AUTHORIZATION TO USE THE EPM FOR TRAINING USE ONLY WITH THE M4, M4A1, M16A4, AND M27 REMAINS THE SAME. 3. ACTION 3.A. PM IWS AUTHORIZES UNITS TO USE THE FOLLOWING POLYMER MAGAZINES WITH THE M4, M4A1, M16A4, M27, AND M249: NSN 1005-01-615-5169 (BLACK) AND NSN 1005-01-659-7086 (COYOTE TAN). UNITS ARE AUTHORIZED TO REQUISITION THESE MAGAZINES WITH UNIT FUNDS. 3.B. PM IWS WILL UPDATE SL-3S FOR THE M4, M4A1, M16A4, AND M27 TO LIST THE ABOVE POLYMER MAGAZINE NSNS. NO OTHER POLYMER MAGAZINES ARE AUTHORIZED FOR USE. 4. IOT PROVIDE IMMEDIATE AND SUSTAINING ACCESS TO ALL USERS, A PUBLICATION CONTROL NUMBER (PCN) WILL BE ASSIGNED TO THIS MESSAGE FOR ACCESS VIA THE WEAPONS SYSTEM ID NUMBER SEARCH IN SL-1-2.// "
The truth is when I spend my own money on mags I buy Lancer mags, but I have a crap load of pmags.
Out of hundreds of Colt rifle's where I work we have no issues with PMAGs.
My take away from this experience is BCM is not at the same level as Colt or other top level manufacturers. I will get rid of this lower, and move on. I'll also refrain from future purchases of critical components manufactured by BCM.
Not trying to shit talk at this point but my BCM factory BFH upper is the least accurate out of two uppers built with Noveske barrels and an upper built with a Colt barrel.
I do love BCM's charging handles, grips, and VFGs.
Moral of the Story:
I am glad I just stuck to buying reputable GI mags.
I have a few PMAGs, some the Second Amend mags, but overall. I just stick to what I have the most invested in: Aluminums.
In the SHTF scenario, I hope my lower will fit, but I also know it likely wouldn't be a fantasy game-like situation where I'll be ripping clips off dead enemies going for a 25 kill streak for the Tactical Nuke.
ETA:
Ironically, I can thank Adams Arms for selling me my first AR with aluminum Colt Mags.
After reading through this thread and a detailed prior thread including a Magpul response, I will certainly be checking this when my new BCM lower arrives at the FFL in a couple days. I understand that this isn’t a BCM fault, and I appreciate their response here, but if the lower doesn’t function with my Pmags, I’ll return it to Primary Arms and order a less expensive Sionics. I fall to the side that one of these items has a government contract for use in battle en masse, and I would want my equipment to match that, if reasonably possible.
I hope mine is in the functioning range, as it seems that most BCM lowers really don’t have this issue.
Beat Trash
03-16-18, 17:18
Beat Trash had the same problem a few years ago.
https://www.m4carbine.net/archive/index.php/t-169913.html
I had this issue in 2015 when putting together a gun to be used as a personally owned/departmentally approved patrol rifle. The lower I bought was going to be paired with a BCM factory assembled upper. When I observed the issue with the MagPul M3 magazines not seating properly, I contacted BCM's customer service, hoping the issue would be resolved. To their credit, they had me ship the upper and lower back for inspection.
The upper and lower were returned with a note saying they were within spec for BCM. The note stated that portion of the forging that was an issue was not part of the original TDP, therefore, they did not consider it an issue, so long as one used Mil spec magazines. I called the CS department back and was given the same information about only using mil spec magazines in their lowers. Once that was said, the CS rep proceeded to convince me that I should purchase and use the Tango Down ARC magazines that his company sells (Not a Mil Spec Magazine...).
My agency had around 300 S&W M&P15's fielded at the time. And the agency was transitioning over to the MagPul M3 magazine (They have since purchased a substantial amount of additional rifles). These guns didn't have an issue with the MagPul M3 magazine, nor did any of the Colt 6920's in my safe. When I mentioned that during my conversation with the CS rep, he proceeded to share his opinion on why an agency should never issue the M3 magazine as it's a liability issue that could get people hurt or killed. I distinctly remember this conversation when I first read that the Marine Corps was adopting the MagPul M3 magazine as their go-to issued magazine. As a Former Marine, I tend to believe the the Marine Corps knows a thing or two about small arms. Apparently they do not think the MagPul M3 magazine is a liability issue.
I realize that now, as well as in 2015 when I started the linked topic that there are a lot of BCM supporters on this site. I actually caught a lot of hate for starting the original topic. My intent then was not to bash a company, but to let other consumers know of a potential issue. Especially any fellow LEO's who planned on using this product as a Patrol Rifle. BCM can make some outstanding products. In 2015, I owned two of their factory uppers built around their ELW barrels and using their gunfighter comp. The paring of the two made for an excellent upper. But my personal experience in dealing with their company, especially the followup phone conversation I had with their CS, left a very bad taste. so much so that I should off every BCM product I owned.
If you own a BCM lower that will seat a MagPul M3 magazine, or if you own a BCM lower and never intend on using a MagPul M3 magazine, more power to you. I'm sure it will give you good service. But after my personal experience when dealing with their company, I will not purchase another one of their products. When officers approach me for recommendations or advice, I can not in good faith recommend BCM after my experience. Especially when working for an Agency that issues the MagPul M3 magazines.
Doc Safari
03-16-18, 17:23
I don't think there is an issue of tolerance stacking. As previously stated the Army and USMC approved the M3 PMAGs for combat use after thorough testing. I don't want to talk out of my ass, but I'm sure that potential tolerance stacking issues would be identified. There's no way they would approve a mag that would fail to function in a percentage of their weapons.
I tried 7-8 M3 PMAGs in the lower in question. They all failed. This lower is clearly off. On all my other rifles the magwell is even with the trigger guard. On the BCM lower the magwell extends below the trigger guard. I don't want to be a crybaby, but I am dissapointed. Something either meets the standard or it doesn't. This item clearly doesn't meet the standard.
I'll probably either sell this lower or put it on my beater gun.
See the picture below. I should add both trigger guards are the same design. The only difference is the logo on them.
51043
We've seen this photo now, and a diagram posted by Bravo Company.
Note how in the photo the front trigger guard portion of the receiver clearly protrudes past the trigger guard on the receiver that is a "No Go" with Gen 3 Pmags.
I'm wondering if this photo is a "ballpark" approximation of whether a Gen 3 PMag will work in a BCM lower without having to get out the calipers and take measurements. In other words, if you own a BCM lower, it would be helpful to know if you can purchase Gen 3 PMags for it before you place an order.
Is that photo enough that you can get out your own BCM lower and "eyeball it"?
How about it? Is this photo a good rule of thumb? Or does it take actual measuring?
First off I love BCM and use a 11.5 BCM as my go to upper. Its sits on a Umbrella Corp lower for just this reason. Personally I think this war is lost. BCM, KAC and any other lowers that have any issues with gen 3 pmags in anyway need to solve this issue like Noveske did. If I was BCM I would be pissed but now that they are issued the conversation should be over.
Doc Safari
03-16-18, 17:40
First off I love BCM and use a 11.5 BCM as my go to upper. Its sits on a Umbrella Corp lower for just this reason. Personally I think this war is lost. BCM, KAC and any other lowers that have any issues with gen 3 pmags in anyway need to solve this issue like Noveske did. If I was BCM I would be pissed but now that they are issued the conversation should be over.
I hate to say it, but I tend to agree.
Magpul mags are ubiquitous: it's unlikely that will change. They are not some niche accessory. They are more than mainstream, warts and all.
If BCM were dedicated to making a 100% milspec weapon I might think that they are right to stand their ground and stick 100% to print. HOWEVER, I just bought a BCM lower with the Gunfighter stock, BCM polished nickel teflon BCG, and Mod 3 pistol grip. The upper came with the gunfighter compensator.
Clearly none of these additions are what you'd find on a dot-mil-issued weapon (unless I'm horribly mistaken), so BCM is basically conceding that not every component has to be 100% what the military issues. These are fine accessories, but they are NOT what you'd find on a strict military configuration. (Again, unless I'm totally mistaken).
Therefore it's not that much of a stretch for BCM to start making lower receivers with a slight modification that isn't technically "milspec."
I would think that this controversy over Pmags would end up costing them sales. Just read some of the replies to this thread. They would be smart to allow this one deviation to their copy of the TDP in order to please customers. As I pointed out in the accoutrements added to my rifle above, they have already set the precedent to deviate somewhat from strictly military configuration.
Yes, it sucks to have to change a dimension or two just to accomodate an accessory, but it sounds like that's what the market will bear.
MagPul made their Gen 3 mag to work in a lower receiver of Colt specs, right or wrong, and that is becoming the acceptable standard just because Pmags are everywhere and not going away anytime soon.
I realize this could result in a major supply or manufacturing change on BCM's part: not a cheap prospect. But the alternative might be to gain a reputation for not working with magazines that have taken over a huge portion of the market.
As an analogy, imagine an AK that only works with bakelite mags even though cheap steel surplus mags are everywhere and you can see how that would hamper sales of that particular weapon.
We live in a World made to a dimension with a tolerance.
BCM just tells it like it is, and knows what the spec is to back it up. Most have no idea what the spec is, will test fit a mag in a replacement lower, and hope you don't complain about them on the internet.
Now imagine both are waiting on a single part to come in so they can ship a large rifle order. Who is going to ID parts that are out of spec? More important who do you think will send those parts back and wait for parts that are in spec?
I try all my rifles or lowers for Gen 3 comparability before I buy them or do the transfer on an online lower purchase .
One thing we should note is that BCM has a more flared magwell than Colt, which most people would agree is an upgrade to milspec and you really can’t say the Colt is of higher quality for that reason.
However, I don’t see why BCM can’t make a slight adjustment to that area of the lower while still maintaining the flare. Magpul had more of a valid reason for the tab than BCM has for them mags not fitting. This issue won’t go away, they’re just doing themselves a disservice. I’m a huge BCM fanboy and will continue to buy their products but no more lowers.
Sent from my iPhone using Tapatalk
One thing we should note is that BCM has a more flared magwell than Colt, which most people would agree is an upgrade to milspec and you really can’t say the Colt is of higher quality for that reason.
However, I don’t see why BCM can’t make a slight adjustment to that area of the lower while still maintaining the flare. Magpul had more of a valid reason for the tab than BCM has for them mags not fitting. This issue won’t go away, they’re just doing themselves a disservice. I’m a huge BCM fanboy and will continue to buy their products but no more lowers.
Sent from my iPhone using Tapatalk
The reason it is “more flared” is because there is more material hanging down to flare. If it was the same as the colt then the flare would be the same.
I think if you buy a non blem lower it should work with a gen3 pmag. Pmag is an industrial standard. Hell, they maybe more popular than aluminum mags. Basically if we as a forum stop accepting BCM’s excuses then they would have to change it. I’m a bcm fanboy but if another company had this problem, especially ones m4 looked down on, this site would be bashing the shit out of that company. Let’s get real people.
Due to the thread from ‘15 I haven’t purchased any other BCM lowers. They have lost several sells from me due to their response. But now I several battle arms, and colt lowers that work perfectly with pmags. CS makes or breaks a company.
Pmag is an industrial standard.
No, M-LOK is a standard. With a print.
Lobby MAGPUL to put out an actual dimension that is compatible, then ask manufacturers to add that dimension. This is really quite simple.
Point to an issue rifle that will not take a Gen 3 PMAG, COLT, FN, HK® 416 and MR556A1, M27 IAR, British SA-80, and even the FN® SCAR™ MK 16/16S all work with them. For BCM to make the claim that it is a non mil spec magazine problem and not their problem is ludicrous when they work in all those issued rifles. They have a NSN, is the only magazine the USMC will take to war, approved issue for Army and Air Force yet BCM is OK with building non compatible lowers. I don't know why they want to take a stand on this when it is not that hard to fix but so be it, I will now lump BCM lowers in with all the older silly Colt lowers with non standard pins, sear blocks etc and will not own one.
'
To me that is pretty much an industrial standard if it works with just about all other lowers and several different Firearms.
Point to an issue rifle that will not take a Gen 3 PMAG, COLT, FN, HK[emoji768] 416 and MR556A1, M27 IAR, British SA-80, and even the FN[emoji768] SCAR[emoji769] MK 16/16S all work with them. For BCM to make the claim that it is a non mil spec magazine problem and not their problem is ludicrous when they work in all those issued rifles. They have a NSN, is the only magazine the USMC will take to war, approved issue for Army and Air Force yet BCM is OK with building non compatible lowers. I don't know why they want to take a stand on this when it is not that hard to fix but so be it, I will now lump BCM lowers in with all the older silly Colt lowers with non standard pins, sear blocks etc and will not own one.
'
I have two BCM SBR’s. I have no freaking idea what generation my PMags are. How do I tell? Every mag, including PMags! I’ve used have worked.
Sent from my iPad using Tapatalk
The Gen 3's have the dot matrix pattern for numbering and the over insertion tab at the rear.
I have two BCM SBR’s. I have no freaking idea what generation my PMags are. How do I tell? Every mag, including PMags! I’ve used have worked.
Sent from my iPad using Tapatalk
It’s definitely not an issue with all BCM lowers. The one I have works fine with every M3 PMAG I’ve tried so far.
There are plenty of other flared lowers that the mags will work with too.
Sent from my iPhone using Tapatalk
The issue isn't with the design. It's with the tolerances that BCM considers acceptable.
This definitely doesn't affect all BCM lowers.
Does anyone know what mags their complete rifles come with?
My complete BCM rifles came with D&H mag with a BCM floor plate
I have four BCM lowers. Every one of them functions fine with every generation of PMAG I've used, as well as with Lancer mags and USGI mags.
I can tell no difference between them and my Colt lowers, functionality wise. Of course, that doesn't mean there isn't an issue either..
I honestly wonder what percentage of their lowers have issues with PMAGS.
Sent from my SM-N910P using Tapatalk
I have four BCM lowers. Every one of them functions fine with every generation of PMAG I've used, as well as with Lancer mags and USGI mags.
I can tell no difference between them and my Colt lowers, functionality wise. Of course, that doesn't mean there isn't an issue either..
I honestly wonder what percentage of their lowers have issues with PMAGS.
Sent from my SM-N910P using Tapatalk
The fact that a certain percentage of their lowers won't works with Gen 3 PMAGs is only half the issue... The other half is their attitude concerning this incompatibility.
Frankly, they just lost another couple of sales from me and my buddy because of this. Can't stand "it's not our problem" attitude kind of customer service.
FWIW, my brand new BCM lower accepts Gen 3 Pmags without issue.
To me that is pretty much an industrial standard if it works with just about all other lowers and several different Firearms.
"Pretty much" and "just about" is not how anything is made to a standard. I'm a machinist, I make parts to a print with dimensions and an allowable tolerance. It's a Engineer's job to make that tolerance reasonably large to keep the price low, while being fully functional in relation to other parts and their tolerances.
If I make a pile of parts most of them will be right about in the middle of the tolerance (if I do my job right) but that doesn't mean that the few that use almost all of the tolerance are wrong. It either meets the print spec and is 100% good or it does not and is 100% bad.
Every major companies lowers are "in spec" the overwellming majority of the time, yes, a few bad apples might pass, but you can still buy a lower with confidence. After a quick Google search, there are a lot of issues with M3 mags and different companies lowers. None of this was a problem until Magpul released the M3. Now people are bashing the companies (Like BCM-who, by my knowledge, doesnt even produce their own recievers) lowers because "some" won't work with a $12 piece of plastic...
Here's a crazy thought...just buy M2's. Their cheaper too.
Maybe Magpul should've stated that the over insertion tab (that makes this particular mag work on more platforms) may have issues with a few lower receivers.
*Side note, I only have 10 M3's, and they fit all my lowers BCM (3) AERO (1) COLT (1)
jackblack73
03-17-18, 18:13
I'm a huge fan of both BCM and Magpul, and I don't see how people can blame BCM here. That over-insertion tab is clearly not part of any spec since other mags don't have it. Magpul should have made their mags compatible with all lowers, not the other way around. I think Magpul was probably targeting military sales, so that's why they focused on Colt lowers when designing the mags. But just because the mags are prevalent, are manufacturers of lowers like BCM and KAC supposed to adapt? What if another accessory product becomes prevalent, are they then expected to adapt then too? It should be the other way around. That said, I do wish would BCM would just go ahead and change their spec to adapt to what I consider to be Magpul's screw up.
Every major companies lowers are "in spec" the overwellming majority of the time, yes, a few bad apples might pass, but you can still buy a lower with confidence. After a quick Google search, there are a lot of issues with M3 mags and different companies lowers. None of this was a problem until Magpul released the M3. Now people are bashing the companies (Like BCM-who, by my knowledge, doesnt even produce their own recievers) lowers because "some" won't work with a $12 piece of plastic...
Here's a crazy thought...just buy M2's. Their cheaper too.
Maybe Magpul should've stated that the over insertion tab (that makes this particular mag work on more platforms) may have issues with a few lower receivers.
*Side note, I only have 10 M3's, and they fit all my lowers BCM (3) AERO (1) COLT (1)
I'm a huge fan of both BCM and Magpul, and I don't see how people can blame BCM here. That over-insertion tab is clearly not part of any spec since other mags don't have it. Magpul should have made their mags compatible with all lowers, not the other way around. I think Magpul was probably targeting military sales, so that's why they focused on Colt lowers when designing the mags. But just because the mags are prevalent, are manufacturers of lowers like BCM and KAC supposed to adapt? What if another accessory product becomes prevalent, are they then expected to adapt then too? It should be the other way around. That said, I do wish would BCM would just go ahead and change their spec to adapt to what I consider to be Magpul's screw up.
http://soldiersystems.net/2016/12/19/usmc-authorizes-gen-iii-pmag-for-m27/
http://soldiersystems.net/2016/12/19/usmc-authorizes-gen-iii-pmag-for-m27/
deleted tinfoil hat stuff
Inkslinger
03-17-18, 19:25
What came first, the AR15 lower and the dimensional specification required for it to function correctly or the Gen 3 Magpul magazine? Personally, BCM is still good to go in my book. YMMV. Is over insertion an issue generally? I’ve never experienced it? Mine works with Gen 3, but I have enough Gen 2’s that I don’t think I ever need to worry.
Here's a crazy thought...just buy M2's. Their cheaper too.
They’re*
And you should probably do some more research on the M3 mag.
Sent from my iPhone using Tapatalk
"Pretty much" and "just about" is not how anything is made to a standard. I'm a machinist, I make parts to a print with dimensions and an allowable tolerance. It's a Engineer's job to make that tolerance reasonably large to keep the price low, while being fully functional in relation to other parts and their tolerances.
If I make a pile of parts most of them will be right about in the middle of the tolerance (if I do my job right) but that doesn't mean that the few that use almost all of the tolerance are wrong. It either meets the print spec and is 100% good or it does not and is 100% bad.
I’m not talking about industrial standard as a spec, I’m talking about industrial standard as in it is THE magazine that’s excepted as the standard in today’s time and it’s THE magazine as all others are judged by. It’s the magazine of the time in the civilian world
I have a KAC lower that does not accept NHMTG mags, but works with every p-mag I own.
I'd let KAC know about that. NHMTG and Okay are the same mags and the same mags that KAC uses.
What came first, the AR15 lower and the dimensional specification required for it to function correctly or the Gen 3 Magpul magazine? Personally, BCM is still good to go in my book. YMMV. Is over insertion an issue generally? I’ve never experienced it? Mine works with Gen 3, but I have enough Gen 2’s that I don’t think I ever need to worry.
I've seen it twice and it was with a P Mag in an old Colt M16 lower(serial. Number 330,000 range) with a a a BCM upper. UNK what generation. The malfunction it caused was a complete Cluster and needed tools and quite a bit of time to fix. The rounds were on top of the BCG. Is this a PMag issue?
Sent from my iPhone using Tapatalk
I had a couple of BCM lowers a few years ago that wouldn't accept M3s.
I don't think BCM's not Mil-Spec excuse holds water. If the mahs weren't compatible with the entire spec range of Mil-Spec lowers, then the military would have to weed out all their non-compatible lowers to use 'em.
Yeah not digging the BCM response in 2018 after Gen 3's being around since 2011, here is a Magpul comment from 2012:
"I asked Magpul’s Drake Clark about this issue. He made this statement …
The M3 design was based off years of feedback from endusers. We knew going into the design phase that there are some lowers that are not going to work with the M3 as the magwell spec they are built to is different from the original Colt design, specifically in the area where the over travel stop interfaces with the area just forward of the trigger guard. These lowers represent less than 1% of the total lowers in the marketplace. We already had direct communication with a few manufactures who build lowers with conflicting interfaces, including POF. Changes will be made to their design to allow comparability. When these changes will be introduced into full production I am not sure. I can say some that have recognized this issue have already been addressed it, such as Noveske.
And for those that have older design lowers that are not comparable with the M3, they have two choices. Use the MOE PMAG or modify the M3 by removing the over travel stop to allow for proper interface.
In all fairness to Magpul, the M3 is compatible with more firearms than any of their previous PMAGs. For >99% of users this will not be a problem. I expect the few manufacturers who are producing incompatible designs will soon change them, it being an easy issue to address."
The reason it is “more flared” is because there is more material hanging down to flare. If it was the same as the colt then the flare would be the same.
I think if you buy a non blem lower it should work with a gen3 pmag. Pmag is an industrial standard. Hell, they maybe more popular than aluminum mags. Basically if we as a forum stop accepting BCM’s excuses then they would have to change it. I’m a bcm fanboy but if another company had this problem, especially ones m4 looked down on, this site would be bashing the shit out of that company. Let’s get real people.
Due to the thread from ‘15 I haven’t purchased any other BCM lowers. They have lost several sells from me due to their response. But now I several battle arms, and colt lowers that work perfectly with pmags. CS makes or breaks a company.
FWIW my BCM that works with M3 PMAGs is a "blem" lower that was bought from Grant. I'm not sure there's even a blemish on it to tell you the truth.
Just to add my two cents, my BCM lowers, both manufactured 2016-later, have no compatibility issues with any of the dozens of 20, 30 or 40 round M3 PMAGs that I have.
Since I mentioned I would be purchasing a lower, I wanted to follow up on that.
I received the lower and tested two 30rd and one 20rd M3 PMAG and all locked in easily and smoothly. No problems at all. BCM responded very quickly (before 0700 after my email at 2229) to my inquiry, and they stated a manufacture date of February 2017.
TopPlinker
03-23-18, 10:21
My findings: I just got last night from my FFL a transfer on a brand new BCM Lower I purchased last week and I tested my older BCM Lower (Nov 2015) and both accept all my Magpul M3 Mags and I tested 10rd, 20rd, 30rd, 30rd Window, 40rd, 30rd 300BLK and a D60. Both lowers worked great with them all and did not seem tight when locking up and all the stick mags dropped free easily when empty. In fact the bigger ones shot out of the magwell better than my other lowers. I did not try the D60 for drop free.
The other people that shoot BCM Lowers ~3-4 people at matches over the past 2 years at my club also have run M3 40rd mags and they all seemed to work just fine. So I assume it is most likely a small subset of there lowers that are having issues. Would be nice to figure out how small or large that subset is though.
51267
BCM has terrible customer service. Purchased a complete upper from them several years ago when the KMR first came out. The barrel was bad from the get go. Tried for months for a resolution before removing the barrel and going with another manufacture who stands behind there product. Still have the stupid thing.
51267
BCM has terrible customer service. Purchased a complete upper from them several years ago when the KMR first came out. The barrel was bad from the get go. Tried for months for a resolution before removing the barrel and going with another manufacture who stands behind there product. Still have the stupid thing.
What's wrong with the barrel?
51267
BCM has terrible customer service. Purchased a complete upper from them several years ago when the KMR first came out. The barrel was bad from the get go. Tried for months for a resolution before removing the barrel and going with another manufacture who stands behind there product. Still have the stupid thing.
Care to document the communication between you and BCM??? I didn't think so.
51267
BCM has terrible customer service. Purchased a complete upper from them several years ago when the KMR first came out. The barrel was bad from the get go. Tried for months for a resolution before removing the barrel and going with another manufacture who stands behind there product. Still have the stupid thing.
I’m not sure what this has to do with PMAGS not fitting in BCM lowers.
They’re*
And you should probably do some more research on the M3 mag.
Sent from my iPhone using Tapatalk
Don't quote me on this... but IIRC there was post here in an M3 mag thread by the magpul rep that stated current production MOE pmags also use the M3 body material. Granted, I'm sure there are other things that make the M3 better too, but I don't think you're losing out to much strengthwise on an AR platform with current production MOE mags unless maybe you're running 855A1 or something.
As far as the BCM lower "thing" we're going over yet again...
Yeah it sucks, and I can't say I totally agree with BCM's handling of this, BUT apparently they're not the only one. It seems between forged lower TDP and magazine TDP there must be some tolerance deviations that don't play well with each other occasionally. More's the pity.
I had a BCM lower I bought in 2016. Pretty sure it was a blem. All mags I had worked fine, however, once made aware of this issue, I did a check of the lower with a M3 Pmag. It seated fine, but I did notice that on one side the spacing between the over-insertion stop and magwell body was very close- tab was almost touching the lower- I'm pretty sure my pictures are still up in whatever thread it was in. Perhaps that was the blem since I couldn't find anything else? Who knows.
But yeah, apparently there's not just one basic type of go/no go tolerance issue.
If that's horrible for you, there's four options:
-buy other lowers to start with
-scream at the moon and sell the offending lower
-sand/file the "off" portions of the lower to correction
-file off the damn Pmag overinsertion tab.
And yes, as I said, I do find this irksome- like most people here I buy from certain brands because I expect boring levels of QC.
That being said, after years of listening to how great DD rifles were, I got the one in a million DD that was royally f***ed up straight out of the box (not to mention their twisting rails issue), then you have Noveske's quirks, etc, etc... so apparently every brand has their "moments" where they don't shine as bright as we'd all like.
HelloLarry
04-04-18, 10:49
I would sell the PMags and go with GI. No compatibility problems with those.
Dr. Bullseye
04-04-18, 12:03
I would sell the PMags and go with GI. No compatibility problems with those.
After 76 posts, the above is the only one that makes sense. Pmag is not the standard, mil spec is the standard. Go to any AR 15 type forum and you will see someone with a particular lower complaining about pmags not fitting properly. It has happened to me. I threw the plastic crap away and went with USGI type mags. No more problems.
I would ditch the lower before I ditched the ability to use every mag on the market.
I would ditch the lower before I ditched the ability to use every mag on the market.This. You never know when you might be in a situation where you need to use a pmag.
Be it in a three gun match, or on the line.
Sent from my Pixel 2 using Tapatalk
Doc Safari
04-04-18, 12:48
This. You never know when you might be in a situation where you need to use a pmag.
Be it in a three gun match, or on the line.
Sent from my Pixel 2 using Tapatalk
Colt receivers use Pmags with no problems.
'Nuff said.
As I've said before: Much as I believe BCM makes a quality product I think they are on the wrong side of this.
51267
BCM has terrible customer service. Purchased a complete upper from them several years ago when the KMR first came out. The barrel was bad from the get go. Tried for months for a resolution before removing the barrel and going with another manufacture who stands behind there product. Still have the stupid thing.
I'll give ya $100 for it
51267
BCM has terrible customer service. Purchased a complete upper from them several years ago when the KMR first came out. The barrel was bad from the get go. Tried for months for a resolution before removing the barrel and going with another manufacture who stands behind there product. Still have the stupid thing.
Can you expand on what "bad" means? Poor finish? Not accurate?
As a BCM distributor, I will tell you that BCM does in fact stand behind their products. What they don't do is allow customers to get refunds when there is nothing wrong....
C4
I would ditch the lower before I ditched the ability to use every mag on the market.
I have lots of lowers that won't work with GEN 3 PMAG's. They are all high level, top quality lowers. So it should be the other way around. Buy mags that your guns like.
C4
Colt receivers use Pmags with no problems.
'Nuff said.
As I've said before: Much as I believe BCM makes a quality product I think they are on the wrong side of this.
I don't have any issues with GEN 2 PMAG's in my BCM lowers.
C4
Doc Safari
04-04-18, 16:07
I don't have any issues with GEN 2 PMAG's in my BCM lowers.
C4
Me either, so far. Isn't the issue only with Gen 3 Pmags and that over-insertion tab?
I've made it a rule to only use Gen 2 Pmags.
Me either, so far. Isn't the issue only with Gen 3 Pmags and that over-insertion tab?
I've made it a rule to only use Gen 2 Pmags.
Yes (and flared magwells).
C4
My Gen 2 Noveske wouldn’t work with them either.
Hell my SCAR doesn’t work with any PMAG without mods.
Don’t think either of them are bad or poor quality.
I threw the plastic crap away and went with USGI type mags. No more problems.
I'm not going to argue if PMAGS are milspec or not, but I would never call them "plastic crap".
I had a box full of unservicable issue mags. I had to replace them every year.
I've been using the same 8 PMAGS as my training mags for 3 years with hundreds of thousands of rounds through them and they are still going strong.
The only PMAGs I've broken so far were some old ass FDE hand-me-downs that already had thousands of rounds on them. I was doing some high volume shooting, 8,000+ rifle rounds in 10 days, and three of them either cracked at one of the feed lips or cracked at the notch for the bolt catch.
I've been trying to sell the lower locally for a couple of weeks now.
If I end up shaving the magwell to accommodate the mags what if any are the negatives losing the anodizing in that area?
Fatorangecat
04-04-18, 18:44
If I were set on using Pmags and keeping that lower I would file it down bead blast and Cerakote it.
When I recently purchased a BCM lower from Primary Arms, I requested they ensure it worked with a Magpul M3. They stated BCM lowers are compatible (maybe now) and M3s do fully insert and lock in my sample of one. LMT has been a sure thing in every way, my favorite lower bar none...
Nightstalker865
04-04-18, 20:28
My Gen 2 Noveske wouldn’t work with them either.
Hell my SCAR doesn’t work with any PMAG without mods.
Don’t think either of them are bad or poor quality.
The SCAR 16S will work perfectly with Gen 3 PMags. No modification needed.
Sent from my iPhone using Tapatalk
I've been trying to sell the lower locally for a couple of weeks now.
If I end up shaving the magwell to accommodate the mags what if any are the negatives losing the anodizing in that area?I was wondering about that too.
Sent from my Pixel 2 using Tapatalk
I've been trying to sell the lower locally for a couple of weeks now.
If I end up shaving the magwell to accommodate the mags what if any are the negatives losing the anodizing in that area?
Always modify the cheapest part. IE: the mags.
The SCAR 16S will work perfectly with Gen 3 PMags. No modification needed.
Sent from my iPhone using Tapatalk
You are correct. I modified all my Gen 1 and 2 mags so I didn't even pay attention.
So I bit the bullet and modified my receiver to accept M3 mags. After 10 minutes with a jeweler's file this is the result. Not a lot of material had to be removed. I'm going to hit it with some Aluminum Black, and the whole rifle is getting a paint job.
Nightstalker865
04-08-18, 11:31
I’m sorry, but that is ridiculous that it even had to be done. With the manufacturing technology available today there is no excuse for this.
I’m a BCM fan, but they dropped the ball on this.
Sent from my iPhone using Tapatalk
jackblack73
04-08-18, 14:45
There are reports of these mags not working with lowers from BCM, Knights, Noveske, and I'm sure others I've missed or forgotten. I don't see why people keep blaming BCM for this.
I’m sorry, but that is ridiculous that it even had to be done. With the manufacturing technology available today there is no excuse for this.
I’m a BCM fan, but they dropped the ball on this.
Sent from my iPhone using Tapatalk
They made the lower to work with in mags that meat the military standards. Gen 3 pmags are outside of those standards. It isn't BCMs fault. Nobody dropped the ball here. It was 2 companies working on products at roughly the same time that ended up leading to an incompatability.
They made the lower to work with in mags that meat the military standards. Gen 3 pmags are outside of those standards. It isn't BCMs fault. Nobody dropped the ball here. It was 2 companies working on products at roughly the same time that ended up leading to an incompatability.
Yet, there are multiple elements within the DOD that have approved or adopted their use.
Nightstalker865
04-08-18, 18:06
They made the lower to work with in mags that meat the military standards. Gen 3 pmags are outside of those standards. It isn't BCMs fault. Nobody dropped the ball here. It was 2 companies working on products at roughly the same time that ended up leading to an incompatability.
It is the Mil standard magazine now. Not to mention the most popular on the civilian market. BCM has known about this issue for a couple years now, yet they apparently haven’t modified their lower specs. There is no excuse for this.
Again, I like BCM and own quite a few of their products, but I cannot recommend their lowers anymore. I hate it, but it’s the truth.
Sent from my iPhone using Tapatalk
I just received one that is compatible, please advise...
Older lowers may not be, but if BCM identified and corrected the problem they are gtg. What is it you want, them to replace a lower that was fine up until M3 appeared?
I just received one that is compatible, please advise...
Older lowers may not be, but if BCM identified and corrected the problem they are gtg. What is it you want, them to replace a lower that was fine up until M3 appeared?
If you read this thread, it's discussed that SOME BCM lowers will work without issue.
The problem is:
The TDP doesn't specify a particular spec for this area. So, BCM uses a forging that, when fresh, might be "too much" material on the rear magwell lip to accommodate the over insertion tab.
I am sure it is within 10ths, or even 32nds, of inches and would be an easy fix, but, they are technically in "MilSpec" per their TDP.
I just received one that is compatible, please advise...
Older lowers may not be, but if BCM identified and corrected the problem they are gtg. What is it you want, them to replace a lower that was fine up until M3 appeared?
Has not been corrected. Read the thread.
If you read this thread, it's discussed that SOME BCM lowers will work without issue.
The problem is:
The TDP doesn't specify a particular spec for this area. So, BCM uses a forging that, when fresh, might be "too much" material on the rear magwell lip to accommodate the over insertion tab.
I am sure it is within 10ths, or even 32nds, of inches and would be an easy fix, but, they are technically in "MilSpec" per their TDP.We keep talking about the TDP, But isn't the only true M16 TDP owned and used by Colt and their licensees? FN etc...
I don't think BCM has legal access to use the Colt TDP, do they? Are they paying Colt royalties?
Sent from my Pixel 2 using Tapatalk
Edit: please correct me if I'm wrong.
SomeOtherGuy
04-09-18, 10:08
The problem is:
The TDP doesn't specify a particular spec for this area. So, BCM uses a forging that, when fresh, might be "too much" material on the rear magwell lip to accommodate the over insertion tab.
I am sure it is within 10ths, or even 32nds, of inches and would be an easy fix, but, they are technically in "MilSpec" per their TDP.
Indeed, and to the extent their lower is within the TDP spec, I can't blame BCM. It would probably be a good business decision to make them compatible with M3 Pmags, but keep in mind that means BCM changing its process to accommodate another manufacturer's part that is not 100% compatible with other TDP-compliant parts. Would anyone be asking BCM to change a process to make their lower work with a random part from UTG or Strike Industries?
I have another maker's lower that won't work with M3 Pmags, and I have never blamed that other maker for it. I think Magpul might want to look at their design here and maybe adjust it for wider compatibility.
It's curious why Colt-made lowers seem to be 100% OK with M3 Pmags though. A conscious choice to keep the magwell on the small end of the TDP tolerance range?
Doc Safari
04-09-18, 10:14
Indeed, and to the extent their lower is within the TDP spec, I can't blame BCM. It would probably be a good business decision to make them compatible with M3 Pmags, but keep in mind that means BCM changing its process to accommodate another manufacturer's part that is not 100% compatible with other TDP-compliant parts. Would anyone be asking BCM to change a process to make their lower work with a random part from UTG or Strike Industries?
On any other accessory I might agree with you, but Pmags are becoming such an industry standard that they are supplanting GI mags in the civilian market. I
literally cannot find a gun shop within 50 miles of me that even has any aluminum GI type mags for sale--but everyone has Pmags. I know it's only the Gen 3's that are in question, but if a buyer is not schooled on the difference or maybe just grabs what's available one can get an unpleasant surprise.
I have another maker's lower that won't work with M3 Pmags, and I have never blamed that other maker for it. I think Magpul might want to look at their design here and maybe adjust it for wider compatibility.
Unlikely since the molds are perfected and they do work with most lowers.
It's curious why Colt-made lowers seem to be 100% OK with M3 Pmags though. A conscious choice to keep the magwell on the small end of the TDP tolerance range?
This is a good question, and gets to the issue of whether BCM's version of the TDP specs is an older variant, or if their specs are complete only in critical areas, or some other reason that we don't know.
Indeed, and to the extent their lower is within the TDP spec, I can't blame BCM. It would probably be a good business decision to make them compatible with M3 Pmags, but keep in mind that means BCM changing its process to accommodate another manufacturer's part that is not 100% compatible with other TDP-compliant parts. Would anyone be asking BCM to change a process to make their lower work with a random part from UTG or Strike Industries?
I have another maker's lower that won't work with M3 Pmags, and I have never blamed that other maker for it. I think Magpul might want to look at their design here and maybe adjust it for wider compatibility.
It's curious why Colt-made lowers seem to be 100% OK with M3 Pmags though. A conscious choice to keep the magwell on the small end of the TDP tolerance range?
The mags were built off the Colt lower. BCM is using a different magwell spec. Completely agree that this not BCM's fault and their answer from early last year was fine but the Gen 3 PMAG is now one of the Mil standard magazines. IMO it needs to be fixed - they are now the problem not magpul.
SomeOtherGuy
04-09-18, 10:29
Unlikely since the molds are perfected and they do work with most lowers.
That word, it does not mean what you think it means! :cool:
Not sure what you mean by "the molds are perfected" but anyway that's not the issue. The incompatible lower is a Noveske gen2 ("Flared, Forged Lower") which I bought around the same time that M3 Pmags were introduced. I'll assume that Noveske had no way of knowing another company was going to make an incompatible but market-dominating magazine at the time they designed their lower. I believe Noveske changed their magwell shape within a year or so to make it work with the M3, but in any event they were innovating one way and couldn't foresee that someone else's actions would cause a compatibility issue.
Doc Safari
04-09-18, 10:31
That word, it does not mean what you think it means! :cool:
Not sure what you mean by "the molds are perfected" but anyway that's not the issue. The incompatible lower is a Noveske gen2 ("Flared, Forged Lower") which I bought around the same time that M3 Pmags were introduced. I'll assume that Noveske had no way of knowing another company was going to make an incompatible but market-dominating magazine at the time they designed their lower. I believe Noveske changed their magwell shape within a year or so to make it work with the M3, but in any event they were innovating one way and couldn't foresee that someone else's actions would cause a compatibility issue.
My only point was that as long as Magpul continues to sell thousands of magazines they won't change anything. If this issue doesn't hurt a rifle or lower receiver manufacturer's business, they won't change anything either.
The mags were built off the Colt lower. BCM is using a different magwell spec. Completely agree that this not BCM's fault and their answer from early last year was fine but the Gen 3 PMAG is now one of the Mil standard magazines. IMO it needs to be fixed - they are now the problem not magpul.
Depends on how you look at it. I have never struggled with over inserting a mag. I have, however bumbled a reload. So flared mag wells aid in me getting the gun back up and running. Now, if you are heavy handed and cause malfunctions by slamming the mag into the gun, then you will have a different POV.
Let us also note where the BCM flared mag well comes from (HK 416). This was done at the request of Mr. Vickers (who worked on the 416 project and saw the value of a flared mag well).
C4
so apparently every brand has their "moments" where they don't shine as bright as we'd all like.
Truth.
To the others that stated read the thread, I did. My request with PA was to verify the lower I received was indeed compatible with M3 pmags which in my mind gave me some recourse if there was an issue. PA stated they were compatible, which in reality might not be an accurate statement, however my singular sample BCM is gtg with M3, as is every LMT lower I have.
Depends on how you look at it. I have never struggled with over inserting a mag. I have, however bumbled a reload. So flared mag wells aid in me getting the gun back up and running. Now, if you are heavy handed and cause malfunctions by slamming the mag into the gun, then you will have a different POV.
Let us also note where the BCM flared mag well comes from (HK 416). This was done at the request of Mr. Vickers (who worked on the 416 project and saw the value of a flared mag well).
C4
Over insertion of mags might be more likely on an active two way range. And the Gen 3 PMAG was designed to be compatible with the HK 416/M27, it is my understanding that is why they moved to over insertion tab to the rear. It's not the mag well flaring that is the problem it is the area around the front of the trigger guard that protrudes a little too much. And yes Noveske had a problem back in 2012 and immediately corrected it going forward, where BCM has dropped the ball is digging their heels in and adopting a "not my problem" attitude. I don't see how they can continue that with the widespread adoption going on in the military.
Over insertion of mags might be more likely on an active two way range. And the Gen 3 PMAG was designed to be compatible with the HK 416/M27, it is my understanding that is why they moved to over insertion tab to the rear. It's not the mag well flaring that is the problem it is the area around the front of the trigger guard that protrudes a little too much. And yes Noveske had a problem back in 2012 and immediately corrected it going forward, where BCM has dropped the ball is digging their heels in and adopting a "not my problem" attitude. I don't see how they can continue that with the widespread adoption going on in the military.
I have about 10 guns that don’t work with GEN3 PMAGS. NOVESKE, DD, Colt, BCM, LWRC, etc. In some instances, I think it is tolerance stacking. I look at as they all work with USGI and GEN 2 PMAGS so it CANNOT be the fault of the lower. I also do not have any issues with the GEN 3’s. I just don’t buy buy them.
C4
Sent from my iPhone using Tapatalk
I have about 10 guns that don’t work with GEN3 PMAGS. NOVESKE, DD, Colt, BCM, LWRC, etc. In some instances, I think it is tolerance stacking. I look at as they all work with USGI and GEN 2 PMAGS so it CANNOT be the fault of the lower. I also do not have any issues with the GEN 3’s. I just don’t buy buy them.
C4
Sent from my iPhone using Tapatalk
Thanks for that.
My old DD lower and Noveske gen2 lower work just fine with my M3 PMAGs.
My old DD lower and Noveske gen2 lower work just fine with my M3 PMAGs.
Like Grant said, Noveske fixed their problem quickly. I have it bookmarked on this site where it was stated, but it was only serial numbers below 4800 that went out not compatible.
If you think about it in another way, BCM uses a 1/7 twist barrel. Hornady 50gr ammo does not shoot that well with this twist rate. Their 70gr ammo does however. Does that mean that Hornady makes poor ammo? Does it mean that BCM's twist rate is a poor choice? No, neither. It just means that not every .223/5.56 load that Hornady makes is going to work well in a BCM barrel...
C4
Differences is 50 grain ammo actually works out of a 1/7, just not ideally vs a mag that won't.
If you think about it in another way, BCM uses a 1/7 twist barrel. Hornady 50gr ammo does not shoot that well with this twist rate. Their 70gr ammo does however. Does that mean that Hornady makes poor ammo? Does it mean that BCM's twist rate is a poor choice? No, neither. It just means that not every .223/5.56 load that Hornady makes is going to work well in a BCM barrel...
C4
Differences is 50 grain ammo actually works out of a 1/7, just not ideally vs a mag that won't.
Not really. I have seen some minute of water buffalo groups once you get past about 100yds. I can also "make" as GEN 3 PMAG work in a BCM lower (with ease).
C4
51477
Current production BCM Lower with a GEN 3 PMAG. :-)
C4
MountainRaven
04-11-18, 13:15
Being MIL-SPEC and being issued are two different things.
PMAGS are not MILSPEC nor are they STANAG 4179 compliant.
GenM3 PMags are military issue.
Colt (and FN) rifles are military issue - and are issued with GenM3 PMags.
HK416s and M27s are military issue - and are issued with GenM3 PMags.
SA80 rifles are military issue.
LMT rifles are military issue - and are issued with GenM3 PMags.
BCM rifles are not military issue.
On any other accessory I might agree with you, but Pmags are becoming such an industry standard that they are supplanting GI mags in the civilian market. I literally cannot find a gun shop within 50 miles of me that even has any aluminum GI type mags for sale--but everyone has Pmags.
I can find metal AR-15 magazines locally all day long. I cannot find USGI metal AR-15 magazines. I believe that the current US Army aluminum magazine (designed for use with M855A1) is not available commercially. And it's inferior to the PMag, anyway.
Like Grant said, Noveske fixed their problem quickly. I have it bookmarked on this site where it was stated, but it was only serial numbers below 4800 that went out not compatible.
I had a Noveske Chainsaw "gen 1" lower that I bought last year, was made in 2016 or 2017, that did not get along with my GenM3 PMags. Some of them worked fine, some of them did not. The lower also did not work with any trigger guard but the aluminum folding variety.
I personally will not be buying any lowers that are not made by LMT, Colt, or the Brownell's retro lowers (I've had two and they both work perfectly with GenM3 PMags) - it isn't worth hoping to get lucky with a BCM or Noveske gen1 lower.
HelloLarry
04-12-18, 09:42
Do the Gen 3 30 round Pmags have problems with loading with a closed bolt or failures to pick up the 1st round of a downloaded mag like the 20 round Pmags?
Do the Gen 3 30 round Pmags have problems with loading with a closed bolt or failures to pick up the 1st round of a downloaded mag like the 20 round Pmags?
I download everything by two rounds. I've seen it with PMAG Gen 3s, I think, when I had a full 30 in there.
HelloLarry
04-12-18, 09:48
I see it a lot with the 20s loaded with 2 and 8 rounds
Do the Gen 3 30 round Pmags have problems with loading with a closed bolt?
No, 30 round PMAG's outperform aluminum GI mags but I don't believe even the newer aluminum have the closed bolt problem. You are talking a Viet Nam era issue, does anyone really believe that it has not been addressed in the last 50 years?
TexasAggie2005
04-12-18, 10:21
Do the Gen 3 30 round Pmags have problems with loading with a closed bolt or failures to pick up the 1st round of a downloaded mag like the 20 round Pmags?
Not with my Colt lowers; all gen3 mags (including 10/20/30/40) rounders all seat with a firm push and a nice click when full to max capacity. No issue with dropping bolt and picking up rounds. Hell, I've never had a single mag attributed failure, but that's probably because I rotate thru training mags so much none have reached failure points. I have never downloaded mags, nor have I ever felt the need to with my gen3 mags.
HelloLarry
04-12-18, 14:24
A kid brought a 20 round Pmag to a HP clinic a few weeks ago. I think it was one of the Gen 3s. The thing would not pick up a round from a 2 round load. He had so many problems with it I told him to never use it again. I've tried the earlier Pmags with the same issues. Not worn out POS, but brand new.
Sorry for resurrecting this thread. I recently bought a BCM lower, before I read this thread. I encountered the same issue with the Pmags Gen 3. I kinda wanna try to fix this issue on my own. I was wondering if I file the circled part, please see pic, would it solve the issue?
http://i64.tinypic.com/361iw.jpg
Would exposing the aluminium after filing compromise the integrity of the lower in any way?
Sorry for resurrecting this thread. I recently bought a BCM lower, before I read this thread. I encountered the same issue with the Pmags Gen 3. I kinda wanna try to fix this issue on my own. I was wondering if I file the circled part, please see pic, would it solve the issue?
http://i64.tinypic.com/361iw.jpg
Would exposing the aluminium after filing compromise the integrity of the lower in any way?
There is more info on this thread, https://www.m4carbine.net/showthread.php?169913-Problem-with-a-new-BCM-lower/page8
See page 8 and 9 for some pics. Yes filing the lower will allow you to run the Gen 3 pmags. It will not compromise the lower functionally. If you can do a decent job with the file then hit it with some brownells aluma-hyde or Birchwood Casey Aluminum Black it will look pretty good too.
It’s sad that they still haven’t done anything about this.
Sent from my iPhone using Tapatalk
It’s sad that they still haven’t done anything about this.
Sent from my iPhone using Tapatalk
I sent BCM an inquiry about this issue and this is their reply:
Hello,
Thank you for contacting us.
The M3 version of the PMag adds an “over insertion tab” on the rear spine of the magazine. Unfortunately, it interfaces with an area of the lower that can vary substantially during the manufacturing of a milspec lower receiver group.
For this section of the weapon you have 2 sets of tolerances; forging tolerances and machining tolerances. When you add them up the Mil-Std TDP finished product has a range. For over 5 decades, the dimensions controlling the lower end of the magwell have been generous with tolerances. Allowing as much as +-.060” of tolerance in the M16, and even more within the M4 requirements, with the majority of the tolerances in the forging. That means lowers can vary by 1/8” in this area!
BCM lower receivers are built within the semi auto versions of those prints. Any AR15 lower built to the correct print could still have this issue with the over insertion tab.
It is not fully backwards compatible. Based on our analysis, the location of the tab is based on a lower built to the center of the tolerance range, which leaves the possibility of up to 1/16” of interference in some cases. We have gone over the documents many times to ensure this is not an oversight on our part. If it was, we would scramble to make it right. We have not found this to be the case though. Due to the allowable tolerances in the mil-spec prints, the tab will work with some lowers, and not in others. This is not specific to BCM and similar situations will arise from many other makers whose tolerances may even exceed the TDP allowances.
The PMag is obviously an excellent design, but this tab has the possibility to cause issues with any milspec lower. As a result it is possible even within the same manufacturer to have it fit some and not on others. If you want an inventory or load out of fully cross compatible mags we recommend you file off a bit of that tab, because while it may fit in the couple of your lowers, and then it may not fit in the next couple of your buddies AR.
Please let us know if we can further assist.
Bravo Company USA, Inc
I liked BCM products, but at this point I will no longer recommend their products to any of my friends. I just don't want them to have to go through the same thing I am going through now.
There are similar responses in this thread, it’s nothing new. Noveske changed their lowers to make them work. And at this point, M3 PMAGs are being issued by at least three of the branches of the military. I still love BCM and all of their other products, but I won’t buy another BCM lower until it’s fixed. Luckily the one I have is fine.
Sent from my iPhone using Tapatalk
I had a gunsmith mill my Noveske SBR to work.
Turned out pretty good.
I'll hit it with some allumahyde until I'm ready to get it re Cerakoted.https://uploads.tapatalk-cdn.com/20180708/64f5af27d8dacc410b6cf2d6772ab0d6.jpg
Sent from my Pixel 2 using Tapatalk
I sent BCM an inquiry about this issue and this is their reply:
Hello,
Thank you for contacting us.
The M3 version of the PMag adds an “over insertion tab” on the rear spine of the magazine. Unfortunately, it interfaces with an area of the lower that can vary substantially during the manufacturing of a milspec lower receiver group.
For this section of the weapon you have 2 sets of tolerances; forging tolerances and machining tolerances. When you add them up the Mil-Std TDP finished product has a range. For over 5 decades, the dimensions controlling the lower end of the magwell have been generous with tolerances. Allowing as much as +-.060” of tolerance in the M16, and even more within the M4 requirements, with the majority of the tolerances in the forging. That means lowers can vary by 1/8” in this area!
BCM lower receivers are built within the semi auto versions of those prints. Any AR15 lower built to the correct print could still have this issue with the over insertion tab.
It is not fully backwards compatible. Based on our analysis, the location of the tab is based on a lower built to the center of the tolerance range, which leaves the possibility of up to 1/16” of interference in some cases. We have gone over the documents many times to ensure this is not an oversight on our part. If it was, we would scramble to make it right. We have not found this to be the case though. Due to the allowable tolerances in the mil-spec prints, the tab will work with some lowers, and not in others. This is not specific to BCM and similar situations will arise from many other makers whose tolerances may even exceed the TDP allowances.
The PMag is obviously an excellent design, but this tab has the possibility to cause issues with any milspec lower. As a result it is possible even within the same manufacturer to have it fit some and not on others. If you want an inventory or load out of fully cross compatible mags we recommend you file off a bit of that tab, because while it may fit in the couple of your lowers, and then it may not fit in the next couple of your buddies AR.
Please let us know if we can further assist.
Bravo Company USA, Inc
I liked BCM products, but at this point I will no longer recommend their products to any of my friends. I just don't want them to have to go through the same thing I am going through now.That reply from bcm is pretty embarrassing for them. I'm a big bcm fan as they make some of the best products available from anywhere. But they really dug in deep to their position on this issue. So what if the blueprint has 1/8" of leeway...they can fix this if they wanted to. People with files are fixing this issue in their kitchens...but but but the blueprint??
This problem is over 3 years old. Magpul isn't changing the over insertion tab, BCM isn't changing their lowers, it appears to be a pissing match.
Somewhere out there is a police officer with a bcm patrol rifle and some nice new spare Magpul mags loaded up and ready to use against some school shooter that he doesn't yet know won't fit or will be a struggle to insert. Pretty serious situation.
Anyways, good luck on this and please post a pic when you are done so others can see. And make sure to file away enough material so there is a nickel thick gap between the lower receiver and the Magpul BCM interference tab when a fully loaded mag is inserted. The gap is there to ensure the mag will lock in place reliably.
Glad I decided to roll my own with Mega Forged lowers when I was considering a full BCM.
That reply from bcm is pretty embarrassing for them. I'm a big bcm fan as they make some of the best products available from anywhere. But they really dug in deep to their position on this issue. So what if the blueprint has 1/8" of leeway...they can fix this if they wanted to. People with files are fixing this issue in their kitchens...but but but the blueprint??
This problem is over 3 years old. Magpul isn't changing the over insertion tab, BCM isn't changing their lowers, it appears to be a pissing match.
Somewhere out there is a police officer with a bcm patrol rifle and some nice new spare Magpul mags loaded up and ready to use against some school shooter that he doesn't yet know won't fit or will be a struggle to insert. Pretty serious situation.
Anyways, good luck on this and please post a pic when you are done so others can see. And make sure to file away enough material so there is a nickel thick gap between the lower receiver and the Magpul BCM interference tab when a fully loaded mag is inserted. The gap is there to ensure the mag will lock in place reliably.
I really don't want to turn this into a BCM bashing post. I truly liked many of BCM's products. I just couldn't, in good faith, recommend any of their products anymore, especially with the kind of customer service I received from them after encountering an issue. Personally, as a consumer, I am fine with companies making mistakes, it is how they handle their mistakes that matters more to me.
I really don't want to turn this into a BCM bashing post. I truly liked many of BCM's products. I just couldn't, in good faith, recommend any of their products anymore, especially with the kind of customer service I received from them after encountering an issue. Personally, as a consumer, I am fine with companies making mistakes, it is how they handle their mistakes that matters more to me.Just to be clear, I'm a bcm fan. Will buy and recommend anything they make, except for their lower.
Leaveammoforme
07-08-18, 11:25
Even Anderson and Centurion lowers work with Gen 3's. It isn't the magazine.
http://i.imgur.com/HqvIQwS.jpg
I really don't want to turn this into a BCM bashing post. I truly liked many of BCM's products. I just couldn't, in good faith, recommend any of their products anymore, especially with the kind of customer service I received from them after encountering an issue. Personally, as a consumer, I am fine with companies making mistakes, it is how they handle their mistakes that matters more to me.
Well I'm sure you can go back to your PSA budget build forum if you like.
Decided to give it a try. Pmags works now.
http://i66.tinypic.com/2dv1s14.jpg
http://i64.tinypic.com/33aqp7r.jpg
http://i63.tinypic.com/xckguq.jpg
http://i64.tinypic.com/2jdi1hf.jpg
Just to be clear, I'm a bcm fan. Will buy and recommend anything they make, except for their lower.
In two posts you've mentioned 'anything they make.'
I'm curious just how much some of the companies actually 'make' versus 'have made' versus 'assemble from OEM sourced parts.'
I'm sure in most cases, either way, it's all good stuff, but in some cases we might begin to wonder were the extra 400 to 500 dollars worth of value lives in Brand A versus Brand X. Or the extra 20 to 30 bucks in the LPK.
Well I'm sure you can go back to your PSA budget build forum if you like.
Edit: Not relevant
wetidlerjr
07-08-18, 15:24
PMAGS I and PMAGS II fit BCM lowers. MAGPUL makes PMAG III and now a few (but not anywhere near all) don't fit BCM lowers that haven't been changed. PMAG III aficionados and mavens now declare BCM must change lowers. MAGPUL doesn't have to change anything and can do no wrong.
Old saying; File on the cheap part.
I sent BCM an inquiry about this issue and this is their reply:
Hello,
Thank you for contacting us.
The M3 version of the PMag adds an “over insertion tab” on the rear spine of the magazine. Unfortunately, it interfaces with an area of the lower that can vary substantially during the manufacturing of a milspec lower receiver group.
For this section of the weapon you have 2 sets of tolerances; forging tolerances and machining tolerances. When you add them up the Mil-Std TDP finished product has a range. For over 5 decades, the dimensions controlling the lower end of the magwell have been generous with tolerances. Allowing as much as +-.060” of tolerance in the M16, and even more within the M4 requirements, with the majority of the tolerances in the forging. That means lowers can vary by 1/8” in this area!
BCM lower receivers are built within the semi auto versions of those prints. Any AR15 lower built to the correct print could still have this issue with the over insertion tab.
It is not fully backwards compatible. Based on our analysis, the location of the tab is based on a lower built to the center of the tolerance range, which leaves the possibility of up to 1/16” of interference in some cases. We have gone over the documents many times to ensure this is not an oversight on our part. If it was, we would scramble to make it right. We have not found this to be the case though. Due to the allowable tolerances in the mil-spec prints, the tab will work with some lowers, and not in others. This is not specific to BCM and similar situations will arise from many other makers whose tolerances may even exceed the TDP allowances.
The PMag is obviously an excellent design, but this tab has the possibility to cause issues with any milspec lower. As a result it is possible even within the same manufacturer to have it fit some and not on others. If you want an inventory or load out of fully cross compatible mags we recommend you file off a bit of that tab, because while it may fit in the couple of your lowers, and then it may not fit in the next couple of your buddies AR.
Please let us know if we can further assist.
Bravo Company USA, Inc
I liked BCM products, but at this point I will no longer recommend their products to any of my friends. I just don't want them to have to go through the same thing I am going through now.
Awesome that they now have a form email for the issue.
I have a feeling this would have been fixed already if Pat was still alive. I am disgusted they are still fighting the issue.
PMAGS I and PMAGS II fit BCM lowers. MAGPUL makes PMAG III and now a few (but not anywhere near all) don't fit BCM lowers that haven't been changed. PMAG III aficionados and mavens now declare BCM must change lowers. MAGPUL doesn't have to change anything and can do no wrong.
Old saying; File on the cheap part.
I agree. If you put enough $$$ in marketing you can make half the world believe anything! With the exception of a handful of Lancers I transitioned away from plastic magazines years ago. Mil spec OKAY magazines work in every lower I've tried including BCM. Since when did MagPul magazine become mil spec??
Since when did MagPul magazine become mil spec??
When they started being issued to troops.
wetidlerjr
07-08-18, 16:55
Originally Posted by Bolverk93
The issue that I take with their answer is that M3 PMAGs are mil-spec in that they have been issued an NSN (1005-01-615-5169) and are approved by the Army and the Marine Corps.
Originally Posted by Renegade
Being MIL-SPEC and being issued are two different things.
PMAGS are not MILSPEC nor are they STANAG 4179 compliant.
Originally Posted by GH41
Since when did MagPul magazine become mil spec?
When they started being issued to troops.
Hmmm...
Hmmm...
I think for my personal usage as a SHTF rifle, I don't really care if a type of mag is mil-spec or not, but rather how widely spread its market is. If 90% of the population is using one type of mag, I better make sure my rifle is compatible with that type of mag, mil-spec or not. If only 10% of the population is using one type of mag, even if its mil-spec it wouldn't be on my priority list for compatibility.
Hmmm...
Bill I retract my comment. It was based out of being lazy. Milspec is not the proper term. They are being issued. They DO NOT have any issue with any Colt or FN lowers I have seen or handled. I think it is likely that pmags will become the new standard. Some may like it and some may not. I don't really care and I personally think that the 3rd gen pmags suck. But it doesn't change the fact if you make a lower that is tier 1 or battle ready you lost the battle and your lower should now work with gen 3 pmags. Carrying around a file to alter any said pmag to fit you gun when you need it is ludicrous.
wetidlerjr
07-08-18, 17:35
Bill I retract my comment. It was based out of being lazy. Milspec is not the proper term. They are being issued. They DO NOT have any issue with any Colt or FN lowers I have seen or handled. I think it is likely that pmags will become the new standard. Some may like it and some may not. I don't really care and I personally think that the 3rd gen pmags suck. But it doesn't change the fact if you make a lower that is tier 1 or battle ready you lost the battle and your lower should now work with gen 3 pmags. Carrying around a file to alter any said pmag to fit you gun when you need it is ludicrous.
I haven't had any problems with IIIs and my BCMs but it is probably just as ludicrous to expect someone to mod lowers they already have to accomodate a mag. PMAG IIIs changed; BCM lowers didn't as far as I can tell. Boils down to a "blame game" I guess and like you, I don't really care all that much either. :smile:
Bill I retract my comment. It was based out of being lazy. Milspec is not the proper term. They are being issued. They DO NOT have any issue with any Colt or FN lowers I have seen or handled. I think it is likely that pmags will become the new standard. Some may like it and some may not. I don't really care and I personally think that the 3rd gen pmags suck. But it doesn't change the fact if you make a lower that is tier 1 or battle ready you lost the battle and your lower should now work with gen 3 pmags. Carrying around a file to alter any said pmag to fit you gun when you need it is ludicrous.
It's worth saying I've had various issues over the years with p-mags on both my colt m16a2 and a colt 6520. Mostly issues with them dropping free. I've also seen the issues with lowers from kac, lmt, mega, stag, bcm, etc.
I haven't had issues with my bcm lowers personally with the newer p-mags I've tried but I generally see it being more of an issue with the mags. Personally I mostly end up using aluminium mags for everything at this point. When shooting with friends or using other guns(scar, fs2000, etc) that don't like a lot of p-mags its easier. I don't care to sit there and check every mag to make sure its safe with all of the guns.
That being said bcm should look at modifying their lowers. The problem isn't just with them though.
It's worth saying I've had various issues over the years with p-mags on both my colt m16a2 and a colt 6520. Mostly issues with them dropping free. I've also seen the issues with lowers from kac, lmt, mega, stag, bcm, etc.
I haven't had issues with my bcm lowers personally with the newer p-mags I've tried but I generally see it being more of an issue with the mags. Personally I mostly end up using aluminium mags for everything at this point. When shooting with friends or using other guns(scar, fs2000, etc) that don't like a lot of p-mags its easier. I don't care to sit there and check every mag to make sure its safe with all of the guns.
That being said bcm should look at modifying their lowers. The problem isn't just with them though.
Part of the update in the M3 mag is to make it better at dropping free. USGI and M3 PMAGs are the only ones that drop free out of my Noveske. The way I see it, the less widely used product should change. I’m willing to bet that there are far more M3 PMAGs in use than BCM lowers.
Sent from my iPhone using Tapatalk
I'm lucky that my BCM likes M3 Magpuls, but if it didn't I would change the lower. Makes more sense to modify one thing and be done with it than to modify each and every magazine.
MountainRaven
07-09-18, 00:24
PMAGS I and PMAGS II fit BCM lowers. MAGPUL makes PMAG III and now a few (but not anywhere near all) don't fit BCM lowers that haven't been changed. PMAG III aficionados and mavens now declare BCM must change lowers. MAGPUL doesn't have to change anything and can do no wrong.
Old saying; File on the cheap part.
How many militaries use BCM lowers?
wetidlerjr
07-09-18, 01:37
How many militaries use BCM lowers?
I think the first post on page 13 deals with that question. You might want to read that. :cool:
I think the first post on page 13 deals with that question. You might want to read that. :cool:
I’m on Tapatalk so I don’t see pages, but I assume that is in reference to the milspec argument here. If it is, I don’t get the hang up on that term nowadays. I feel like there is a pretty good understanding of the companies that produce good stuff and those that produce shit. I typically DGAF if it’s milspec because there is a lot of stuff that is truly better than milspec. It’s not the be all/end all standard, really it’s the bare minimum for being serviceable. Of course there is lots of stuff out there that claims to be better and is not, but again, I think there’s a solid general consensus on the true performance of those products. The M3 PMAG seems to be the future mag of the military, regardless of milspec, TDP, blah blah blah.
Sent from my iPhone using Tapatalk
wetidlerjr
07-09-18, 02:04
I’m on Tapatalk so I don’t see pages, but I assume that is in reference to the milspec argument here. If it is, I don’t get the hang up on that term nowadays. I feel like there is a pretty good understanding of the companies that produce good stuff and those that produce shit. I typically DGAF if it’s milspec because there is a lot of stuff that is truly better than milspec. It’s not the be all/end all standard, really it’s the bare minimum for being serviceable. Of course there is lots of stuff out there that claims to be better and is not, but again, I think there’s a solid general consensus on the true performance of those products. The M3 PMAG seems to be the future mag of the military, regardless of milspec, TDP, blah blah blah.
Sent from my iPhone using Tapatalk
Pretty much.
Sparky5019
09-16-18, 10:20
Every time I get in a BCM lower, I M3 check it immediately. If it doesn’t lock, I contact BCM. They send a call tag for the lower and replace it ASAP; no questions asked.
Every time I get in a BCM lower, I M3 check it immediately. If it doesn’t lock, I contact BCM. They send a call tag for the lower and replace it ASAP; no questions asked.
How many times has that happened? We’ve had several members that have apparently been told by BCM that they don’t consider it a problem and won’t fix it.
Sent from my iPhone using Tapatalk
Sparky5019
09-16-18, 12:24
Every time I’ve emailed them; probably 5 or 6 times over the last couple years. Full disclosure though, I’m 07/02 and not always the end user and these were all new rifles/lowers. They’ve been very fast to ask for the lower back and always say that their armorers are busy and they just want to replace it. They’re always professional and polite.
I’ve heard of people having issues. It’s not been my experience personally. If an end user has an issue, maybe try going through a dealer? That shouldn’t matter but...
ChattanoogaPhil
09-16-18, 14:25
I've read numerous times about BCM's superior quality control in assembly. Given the popularity of PMAGs and this known M3 compatibility issue, would it be an overwhelming QC task to simply insert an M3 into the lower for Go No-Go? Advertise two groups of lowers as M3 Compatible or M3 Not Compatible... just as they advertise their handguards as KeyMod or MLOK compatible. Oh wait... but then how many customers would purposely choose a lower that's not M3 compatible over one that is compatible? hmmmmm.... perhaps therein lies the answer.
Beat Trash
09-16-18, 14:30
How many times has that happened? We’ve had several members that have apparently been told by BCM that they don’t consider it a problem and won’t fix it.
Sent from my iPhone using Tapatalk
I was one of those with issues. I called their CS explaining it was for a duty rifle and my agency was transitioning to the M3 magazines. All I got was a condescending lecture on the dangers of the M3 PMAG and any agency using such was creating a liability nightmare by putting their officers at risk. That any knowledgeable individual or organization would not use M3 magazines.
I thought of that conversation when I heard that the United States Marine Corps was switching over to the M3 magazine...
I sold off the lower, and I sold off two BCM uppers I had. I refuse to do business with them after my experiences with their CS. Nor do I recommend any of their products to anyone asking for advice.
sidewaysil80
09-16-18, 14:37
Good to see their customer service Is improving...
Maybe some day they’ll stand by their products instead of blaming everyone and blacklisting people who report an issue.
I was one of those with issues. I called their CS explaining it was for a duty rifle and my agency was transitioning to the M3 magazines. All I got was a condescending lecture on the dangers of the M3 PMAG and any agency using such was creating a liability nightmare by putting their officers at risk. That any knowledgeable individual or organization would not use M3 magazines.
I thought of that conversation when I heard that the United States Marine Corps was switching over to the M3 magazine...
I sold off the lower, and I sold off two BCM uppers I had. I refuse to do business with them after my experiences with their CS. Nor do I recommend any of their products to anyone asking for advice.
That’s pretty bad. I don’t understand how they could blame anything on the M3 PMAG either. Got it, Magpul is a competitor for furniture and accessories but Magpul doesn’t sell ARs and BCM doesn’t really sell mags. That’s pretty childish and disappointing.
Sent from my iPhone using Tapatalk
Sparky5019
09-16-18, 19:50
Guys, I’m not defending them. I’m simply reporting my results. For the record, there have been issues with the M3s which Magpul is denying out of hand and will not discuss...at all. I use M3sand have had no issues but watch the whole vid from the link below. I can reproduce the issue shown but again it has given me zero issues so I continue to use them. Be careful who you put on pedestals and who you vilify; everyone is prone to put one in left field from time to time. JMHO.
https://youtu.be/4QNQ7IOl5sk
Magpul fixed that over two years ago.
That’s pretty bad. I don’t understand how they could blame anything on the M3 PMAG either. Got it, Magpul is a competitor for furniture and accessories but Magpul doesn’t sell ARs and BCM doesn’t really sell mags. That’s pretty childish and disappointing.
Sent from my iPhone using Tapatalk
I love how they were forced to adopt MLOK because Keymod is dead. I waited a long time to laugh about it, because I knew it was coming, and when Noveske caved, I knew BCM would be right behind them.
Magpul fixed that over two years ago.
Err, fixed what, and is there a mag revision id?
Military selection drove that nail, supposedly on data supporting mlok as the more resilient solution, keymod cracked between slots.
Not taking sides, but posting my results. I suppose you could say BCM is my go-to lower. I have 4 of them, with a 5th on the way. I just checked my 4, and M3 Pmags fit great. Insert easy, with room to spare at the over insertion tab, and drop free. That said, I’ll bring an M3 Pmag to check when I pick up my 5th before doing paperwork. I guess I’ve been lucky so far.
I also checked my other brand lowers with no issue.
**update**
Picked up the 5th BCM lower today. Took an M3 Pmag to test and had no issues.
Err, fixed what, and is there a mag revision id?
The second round crossing up with the top round. There was a guide nub added inside the feedlips of the Gen M3 30s sometime in the first half of 2016.
Chris Bonesteel
09-18-18, 13:29
Cant blame bcm for not wanting to warranty lowers that meet mil spec but are not compatible with aftermarket magazines, however it is totally mind boggling that they wouldnt adjust their specs to fit extremely popular magazines after the issue had come to light, adding one more cut to the operation couldnt possibly add enough expense to justify the alienation of gen 3 pmag users
Apparently the M3s are Mil-Spec enough to have no issues in actual military M27s and M4s.
If a certain percentage of the USMC's lowers didn't work with the M3, they certainly wouldn't have become issued mags.
ruckusjuice
09-18-18, 14:11
I’m also surprised that BCM hasn’t adjusted the range of acceptable tolerances for the area at the front of the trigger guard to always accept Gen M3 PMags. Now that these magazines are issued by the Army, Marine Corps and Air Force, I can’t see any justification that a lower doesn’t need to be able to function with them. Soon Gen M3 Pmags will be as ubiquitous as the aluminum GI magazine.
The early Gen M3 Pmags did sometimes have issues with the tip of the second round moving upwards making it very difficult to lock the mag in under a closed bolt. Magpul has since fixed the issue as already noted. All Sand and MCT mags, and all black mags made from 2016 and later have the additional ribs in front of the feed lips to prevent this issue.
Chris Bonesteel
09-18-18, 14:24
Thats the thing with specs, they are what they are until theyre changed. People confuse spec with compatibility all the time
I'm going to call Toyota and bitch about my Tacoma not being compatible with aftermarket rims. :shout:
Sparky5019
09-18-18, 14:54
I'm going to call Toyota and bitch about my Tacoma not being compatible with aftermarket rims. :shout:
[emoji457]
Sent from my iPhone using Tapatalk Pro
MorphCross
09-18-18, 15:17
I'm going to call Toyota and bitch about my Tacoma not being compatible with aftermarket rims. :shout:
[emoji457]
I wouldn't say it is a 100% accurate analogy however the sentiment is on point.
Doesn't "standardizing" on a magazine that is optimized to work on Colt Lowers alone defeat the purpose of STANAG 4179 which is all about interoperability between allied NATO forces?
Also why does it matter when an end user can rework a little bit of polymer to resolve the issue?
Sparky5019
09-18-18, 15:18
I wouldn't say it is a 100% accurate analogy however the sentiment is on point.
Doesn't "standardizing" on a magazine that is optimized to work on Colt Lowers alone defeat the purpose of STANAG 4179 which is all about interoperability between allied NATO forces?
Also why does it matter when an end user can rework a little bit of polymer to resolve the issue?
Maybe I should have expounded more...[emoji457]🤦🏼[emoji849]
Sent from my iPhone using Tapatalk Pro
The second round crossing up with the top round. There was a guide nub added inside the feedlips of the Gen M3 30s sometime in the first half of 2016.
Thank you, I have both on hand.
Chris Bonesteel
09-18-18, 17:00
I'm going to call Toyota and bitch about my Tacoma not being compatible with aftermarket rims. :shout:
If those rims are compatable with every other brand of light truck, show marked advantages, are the most ubiquitous rims available, in stock at every tire store, and the only aftermarket rims approved by the dot, Toyota would be foolish to (solely as a matter of pride, would still interface with factory rims equally well) refuse to adjust the program they use on their hubs, years after they discovered the incompatibility.
I wouldnt expect bcm to warranty over the issue, if their lowers meet mil spec, or to change if it somehow comprimised the lower in other ways, but not changing the spec after the issue is discovered seems to me nothing but a matter of arrogance, maybe there is more justification for it, but i cant see it, each receiver is fixtured and machined machining that one flat cant be anything
If those rims are compatable with every other brand of light truck, show marked advantages, are the most ubiquitous rims available, in stock at every tire store, and the only aftermarket rims approved by the dot, Toyota would be foolish to (solely as a matter of pride, would still interface with factory rims equally well) refuse to adjust the program they use on their hubs, years after they discovered the incompatibility.
I wouldnt expect bcm to warranty over the issue, if their lowers meet mil spec, or to change if it somehow comprimised the lower in other ways, but not changing the spec after the issue is discovered seems to me nothing but a matter of arrogance, maybe there is more justification for it, but i cant see it, each receiver is fixtured and machined machining that one flat cant be anything
Have to agree to both of these.
Sent from my iPhone using Tapatalk
Chris Bonesteel
09-18-18, 19:51
Also, i hate to be the guy to say this, but just because bcm has a well earned reputation for quality parts, it doesnt make them any less "aftermarket" than magpul.
ChattanoogaPhil
09-19-18, 12:31
I wouldn't expect BCM to change their specs. BCM should manufacture their rifles to specs they see fit. However, since this is a known ongoing issue with such popular magazines it would seem reasonable for BCM to inform their customers so they can make an informed purchase.
Website update: BCM lowers may or may not accommodate M3 magazines.
Minimal effort to inform customers. Is that too difficult a task? Maybe it is just too much... else BCM could have made a single sentence website update rather than lengthy explanations on Net Forums and repeated returns on lowers as earlier posted here.
Hey guys checkin in on December of 2018, any updates to this situation?
Powered by vBulletin® Version 4.2.5 Copyright © 2024 vBulletin Solutions, Inc. All rights reserved.