View Full Version : Problems with 20 round PMAG
I have feeding and lock back issues. When I change to my 30 rounder I have no problems. Can I stretch the spring to get a little more force or should I replace the spring entirety?
davidjinks
05-17-13, 13:17
Replace the spring never stretch it.
How many rounds do you have through the mag?
I have feeding and lock back issues. When I change to my 30 rounder I have no problems. Can I stretch the spring to get a little more force or should I replace the spring entirety?
Replace the spring never stretch it.
How many rounds do you have through the mag?
About 30 or 40.
Drop Magpul and email, they're usually good at taking care of issues.
what kind of ammo,gun, lpk are in play here. the mag may not be the issue. i had a bunch of failures to lock back on 2 fresh out of the package pmag m2/30. my lancer awm and pmag m3/30 worked just fine. turns out it was ammo related. if you shoot notoriously under powered ammo(steel, pmc, etc) this may be your issue, espicially if youre shooting a midlength. there are many variables.
My gun shoots flawlessly when I'm using my pmag 30 and has trouble on the 20. Several times I've swapped back and forth and the same. It doesn't always happen but usually after about 3-5 rounds through the 20. The 20 barely locks back when it does and I can pull my bolt back then have to press my bolt catch to fully engage it. Seems like a weak spring to me.
It's not magpul they don't make 15 round magazines. It's been modified by someone else.
Here in Cali we get after market 10/30 round magazines. It has a limiter inside and is then permanetly sealed to comply w/ CA laws. Dependability is usually based on who does the mod.
Here in Cali we get after market 10/30 round magazines. It has a limiter inside and is then permenatly sealed to comply w/ CA laws. Dependability is usually based on who does the mod.
When I lived in Cali the 10/20 pmags were known to perform much better than the 10/30.
It's a 20. I had a brain fart.
It's a 20. I had a brain fart.
You have just the one I assume?
michael word
05-18-13, 18:58
I have had this issue with all my pmags. I had to cut a coil off of the bolt catch spring and worked fine then. I eventually upgraded the springs to extra power chrome silicon springs with no issues now. Happened with both 20 and 30 mags. Used stag LPK by the way, dont know if they make their springs stiffer than others.
You have just the one I assume?
Correct.
I had been using PMAG 30's with absolutely no problems in my AR. I then bought 5 PMAG 20's (middle of 2012) and had the same problems described by the OP with all of them. I finally got all five 20rd mags to work very well.
1) I smoothed all internal seams and lightly sanded the internal surfaces of the magazine shells with 400grit wet-or-dry sandpaper. I then applied a little paste wax to the interiors of the magazine shells. This smoothed out the action and all feeding problems were gone.
2) I found that there was a little too much projection at the rear of the top of the magazines. This extended material on the back of the magazine was providing friction on the front edge of the bolt catch. Trimming about .015" off the back of the magazine (just to the right of the "U" at the rear of the magazine) with a file is all that was required to have perfect bolt latching every time the last round was fired.
If you do some reading you will see that this is quite common with the PMAG 20. It's been talked about here and elsewhere.
I had been using PMAG 30's with absolutely no problems in my AR. I then bought 5 PMAG 20's (middle of 2012) and had the same problems described by the OP with all of them. I finally got all five 20rd mags to work very well.
1) I smoothed all internal seams and lightly sanded the internal surfaces of the magazine shells with 400grit wet-or-dry sandpaper. I then applied a little past wax to the interiors of the magazine shells. This smoothed out the action and all feeding problems were gone.
2) I found that there was a little too much projection at the rear of the top of the magazines. This extended material on the back of the magazine was providing friction on the front edge of the bolt catch. Trimming about .015" off the back of the magazine (just to the right of the "U" at the rear of the magazine) with a file is all that was required to have perfect bolt latching every time the last round was fired.
That's a rather interesting first post. Lacking personal familiarity with their 20 round magazines it would be interesting to see if others beyond the two of you are having the same issue.
Welcome aboard by the way.
Edit: Seems IG was able to clarify yet another issue. But speaking of, have they addressed this? And would you endorse what SkipD did to remedy?
I found one of the older threads and it seems like the most common solution was to just trash the old mag and buy a newer one with the better follower. I don't know what Magpuls response to this has been but I think they should make it right. The mag was fairly cheap I bought it last year but I'm not going to go screwing with it a great deal and either make it worse or void the warranty. I'm going to see what they'll do about it.
If it's this bad of a problem it seems like they'd work with you.
I found one of the older threads and it seems like the most common solution was to just trash the old mag and buy a newer one with the better follower. I don't know what Magpuls response to this has been but I think they should make it right. The mag was fairly cheap I bought it last year but I'm not going to go screwing with it a great deal and either make it worse or void the warranty. I'm going to see what they'll do about it.
If it's this bad of a problem it seems like they'd work with you.Part of my problem (failure to lock the bolt back) was, according to the folks at Magpul, probably due to a minor dimensional difference in my lower (Fulton Armory). The five magazines that I have are from late 2011 production and they said that there weren't any changes made to then-current production as compared to mine. My magazines all have then-current (early summer of 2012) springs, followers, and shells.
Since I'm capable, I found it much easier to troubleshoot and repair the five magazines I already had than to swap them out. All five magazines work as expected today. The action of the followers is extremely smooth, feeding is perfect every time, and the bolt locks back on empty magazines every time.
Is it a Gen3 Pmag 20?
I have had zero issues with my M3 PMag 20. I also have an original Pmag 20 as well, and I could see how those could have problems.
Part of my problem (failure to lock the bolt back) was, according to the folks at Magpul, probably due to a minor dimensional difference in my lower (Fulton Armory). The five magazines that I have are from late 2011 production and they said that there weren't any changes made to then-current production as compared to mine. My magazines all have then-current (early summer of 2012) springs, followers, and shells.
Since I'm capable, I found it much easier to troubleshoot and repair the five magazines I already had than to swap them out. All five magazines work as expected today. The action of the followers is extremely smooth, feeding is perfect every time, and the bolt locks back on empty magazines every time.
Well out of a DD and Noveske FFL I don't see how they could blame my lowers :)
I know what you mean. I'm capable of working on it myself and may end up doing that just on principle would like them to at least acknowledge the problem if they haven't already.
Is it a Gen3 Pmag 20?
I have had zero issues with my M3 PMag 20. I also have an original Pmag 20 as well, and I could see how those could have problems.
It's original. Bought it early to mid 2012 on sale.
I have a few of the "original" PMAG 20's and have seen lockback issues on them. I believe that Magpul has said something about the geometry of the mag being the culprit in the issues that have been seen. They have since corrected this with the GenM3 line.
I played with an M3 20rd mag just yesterday and it locked back 100%. I didn't put enough through it to be able to tell you it's 100% consistent overall, but at least yesterday it was 100%...it definitely seems more consistent and solid, comparatively.
If you do some reading you will see that this is quite common with the PMAG 20. It's been talked about here and elsewhere.
This ^
I bought one Gen2 20 round Magpul PMAG right after getting my rifle. THEN I did all the reading and saw the patterns. I relegated mine to range use only. I didn't get too far with it before it failed to feed on the second to last round out of the mag, which seems somewhat common.
I sold the magazine.
I don't think a new spring will fix anything.
I just picked up 20 round NHMTG magazines instead. Lighter, shorter, more reliable.
Here is an example of a source. If you look around you can probably find them for less.
http://www.buffertech.com/M16-20-round-magazines-new-P151.aspx
ScatmanCrothers
05-20-13, 11:30
I did the same as Warp. Sold off my pmag 20's and went with NHMTG and a few Lancer translucent 20's since they were reviewing well. No hiccups since.
Will try the gen3 magpuls but not until the ones on hand start wearing out.
How does one tell what generation a Magpul magazine is? Is it basically by production dates or is there a "generation" mark on the magazine? I don't know what generations my PMAG 20's and PMAG 30s are and would like to know.
Thanks.
How does one tell what generation a Magpul magazine is? Is it basically by production dates or is there a "generation" mark on the magazine? I don't know what generations my PMAG 20's and PMAG 30s are and would like to know.
Thanks.
Gen2 is identical to Gen1, but doesn't come with the dust cover. The Gen3 has MANY improvements over the Gen1.
http://i477.photobucket.com/albums/rr133/tireerit_photo/Ar15%20pictures/118_zps8d5b4877.jpg (http://s477.photobucket.com/user/tireerit_photo/media/Ar15%20pictures/118_zps8d5b4877.jpg.html)
How does one tell what generation a Magpul magazine is? Is it basically by production dates or is there a "generation" mark on the magazine? I don't know what generations my PMAG 20's and PMAG 30s are and would like to know.
Thanks.
Gen3 will have a curve. Prior ones, which you may want to avoid, will be completely straight.
Magpul's website is a great resource as well. It will detail all of this.
http://store.magpul.com/category/PMAG
I've done enough research this morning to discover that all of my PMAGs (20 and 30 round) are "Generation 2".
Generation 1 had a very different follower than Gen2 and Gen3 magazines. Gen2 and Gen3 followers have a V-shaped notch in the front end to follow the deeper-than-Gen1 rib inside the front edge of the magazine shell. Gen1 followers had a shallow rectangular notch in the front end.
Gen3 PMAGs (especially the 20rd versions) are quite different externally from Gen1 and Gen2, making them a bit easier to recognize than the difference between Gen1 and Gen2.
Mine is straight and IIRC didn't come with a dust cover. I bought it from DSG last year so I'm sure it's a Gen2.
Sorry to necro this thread.
Is there a consensus on the reliability of Gen 3 20 round PMags, are they good to go? If restricted to 20 round magazines would one simply be better off getting traditional USGI 20 round magazines?
The feeding reliability of the 20 round Gen M3 is 100% GTG.
There was a tolerance stacking issue in the initially released magazine, that in some magazines, when combined with some ammunition types, created a condition where the second round could nose up alongside the first. This condition required a bunch of things to line up to manifest itself, but it existed, so we're fixing it. It's innocuous enough that you may not even notice it even if it is occurring with your setup. It doesn't affect feeding at all, just seating force on a closed bolt.
If inserted into a firearm with the bolt open, the condition self corrects, and the magazine feeds 100% normally. Some lowers do not allow seating on a closed bolt with this condition manifesting, however, or require a significant increase in seating force. Once the magazine is seated, however...once again, it feeds normally.
I'm still using some of the magazines that were returned for this issue in my normal rotation...doesn't happen with any of my guns and my ammo...but it does happen with other ammo and other guns. We scratched our heads for a while, as nominally, there was no difference from any other M3s, and the others are completely unaffected. We figured it out, though, once we figured out how to replicate it.
We identified and implemented a fix, and are finishing up testing on that fix right now. It's passed all compatibility and initial function tests (<2000 rds per mag, but many platforms). Final endurance testing (4,000 rds per mag across multiple weapon types (200 loads)) is all that remains. Once we start production again, owners of existing 20 rounders will be able to swap them out if they are experiencing the issue, or just to be sure, and the new 20s going forward will, of course, not have the issue.
Wow, that is one if the most informative responses from a manufacturer I have read. I have a boat load of gen 1 20-rounders. Good to know the details of this. I have only had one glitch with one mag in several years of use. I will keep buying them as needed. Thanks!
Thank you for the informative post.
This is probably a stupid question.
In Maryland 20 rounders are currently legal. Starting Oct. 1, only 10 rounders will be legal (for purchase). If a Maryland resident was to purchase 20 round PMags that are affected by the problem you mention, that Maryland resident will not be eligible to exchange the magazine after Oct 1 because of the new 10 round limitation, correct? Or would it be considered similar to just shipping out the magazine for "repair" and thus no transfer of possession actually occurs.
What about the reports of the second to last round failing to feed?
I read about that from multiple sources...right after I bought one Gen2 20 round PMAG. So I only used it at the range and kept it unloaded otherwise. I ended up having a failure to feed on the second to last round using factory Federal ammunition in a Colt 6920. That is the only failure or stoppage of any kind I have had in ~2,300 rounds through that rifle. (I traded the mag away a short while later)
jerrysimons
09-10-13, 19:41
Are you speaking of initial Gen 3 20s having problems or initial, as in the Gen1/2 20rd mags?
GEN 2 mags with the straight body, the discontinued model, have had issues with some guns. You can't have a true anti-tilt follower in a straight body mag. That's why the Gen 2 20 round was completely replaced with the GEN 3, while the 30 round variant stayed in the line. We just moved CS into a temporary facility, so the move has us back logged. You should hear from them soon. Apologies for the delay.
There are no magazine-related feeding, function, or last round hold open issues that have been reported with the Gen M3 20 rd, as far as I'm aware. And I'm generally fairly aware. :-)
The straight body M2 20 rd PMAGs are no longer in production. All M3 mags have curved bodies. The aforementioned insertion issue was seen in some of the initial M3, curved mags, in some guns, with some ammo. Small number of mags were actually affected.
Are there any plans to possibly revisit the straight body 20 rd mags sometime in the future?
I know that the GenM3 curved mags are a better design than the previous generation 20's, but I still can't stop myself from wanting some more of those damn straight body mags.
Well, that was kind of the problem in the past...Consumers kept asking for a straight body 20. I'll admit...there's something about the form factor that is indeed appealing, and I still have a few straight 20s in my "prairie dog management" kit. It was understood that a curved 20 would be easier and better, but straight won out.
However... you can't put an anti-tilt follower in a straight magazine that needs to feed tapered cartridges. In most in-spec rifles, the straight 20 still worked very well...but a straight mag will never be as reliable as one with constant curve geometry and an anti-tilt follower.
Thus, the GEN M3 20 with constant curve geometry and an anti-tilt follower, just like its big brothers.
The feeding reliability of the 20 round Gen M3 is 100% GTG.
There was a tolerance stacking issue in the initially released magazine, that in some magazines, when combined with some ammunition types, created a condition where the second round could nose up alongside the first. This condition required a bunch of things to line up to manifest itself, but it existed, so we're fixing it. It's innocuous enough that you may not even notice it even if it is occurring with your setup. It doesn't affect feeding at all, just seating force on a closed bolt.
If inserted into a firearm with the bolt open, the condition self corrects, and the magazine feeds 100% normally. Some lowers do not allow seating on a closed bolt with this condition manifesting, however, or require a significant increase in seating force. Once the magazine is seated, however...once again, it feeds normally.
I'm still using some of the magazines that were returned for this issue in my normal rotation...doesn't happen with any of my guns and my ammo...but it does happen with other ammo and other guns. We scratched our heads for a while, as nominally, there was no difference from any other M3s, and the others are completely unaffected. We figured it out, though, once we figured out how to replicate it.
We identified and implemented a fix, and are finishing up testing on that fix right now. It's passed all compatibility and initial function tests (<2000 rds per mag, but many platforms). Final endurance testing (4,000 rds per mag across multiple weapon types (200 loads)) is all that remains. Once we start production again, owners of existing 20 rounders will be able to swap them out if they are experiencing the issue, or just to be sure, and the new 20s going forward will, of course, not have the issue.
Funny you mention this, I had a M3 20rd that did something similar a few times last weekend, loaded to <20rds everytime I've used it. Inserting the mag on a close bolt, the mag appears to lock in, but once firing, a few rounds feed/fire, then click, empty chamber. I can pull the mag out without releasing. This is on a Noveske Gen 2 lower, BCM BCG, Vltor MUR-1A, WOA LPK.
We'll announce soon when we're ready to start swapping out affected M3 20rd magazines with the new mod, but it shouldn't be long.
For those in states with new ban legislation coming into effect, we're still sorting out what we can and can't do.
For those in states with new ban legislation coming into effect, we're still sorting out what we can and can't do.
Thank you. If I were to guess, those of us in ban states are out of luck.
I have a couple pmag 20 rounders. I've had the same issue as you have describe with them with both of my rifles (both are BCM mid length). I mainly shoot federal 55gr. (for those wondering) Like you, when I switched over to my 30 rounders no issues. Long story short, I just took both of the 20 rounders apart cleaned em up real good and that solved the problem for me.
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