View Full Version : Pinned 14.5?
I've read a lot here, including the stickeys, searched a lot here, but I have a couple of questions that just have not been answered that I've been able to find. Here's my first one:
I have a 16" on my POF and a BCM 16" CHF on the way, so my question is really just curiosity. I've learned from reading that a 14.5" barrel with a (longer?) flash suppressor pinned to it allows you to have a shorter barrel without need for a license. However, what's the point? A standard flash suppressor only adds, what, one inch? Why sacrifice an inch and a half of velocity for one inch of length?
:jester:
The only reason I could see that being anyway beneficial is if you want to use a Acog want the BDC to be more accurate. But in all reality I don't see a point of perm attaching a muzzle device to save an inch...
savagesteel
02-11-12, 01:26
I've been considering going with a 14.5 pinned rifle to make it just a little easier on getting the rifle out of the patrol car (Chevy Impala). One inch doesn't seem like much until you are gouging the passenger door or roof with the barrel when trying to deploy the rifle quickly. It would probably shave a few ounces off the weight of the rifle too, if you are worried about such things. If NFA short barreled rifles were allowed by the administrators I would go for a 12.5 inch barrel. But, for someone who is not getting in and out of a vehicle or counting ounces I would stick with the 16 inch barrels to allow for easy take off/on of flash hiders, muzzle brakes, and some of the free float rail systems out there.
It doesn't make much sense unless you actually use the weapon in ways that it matters. If you are a bench shooter, 16, 18, 24 or whatever is all a moot point. If you are a cop who is pulling it out of your cruiser, or clearing buildings, you will see and feel a difference.
The other reason is also pretty simple, its just because you want to. Modern rails allow you to install what you want, and if you can't figure out what muzzle device you need, then stick with a 16".
The point is that you grasped it rather quicker than others. In actuality there is virtual no difference.
I've read a lot here, including the stickeys, searched a lot here, but I have a couple of questions that just have not been answered that I've been able to find. Here's my first one:
I have a 16" on my POF and a BCM 16" CHF on the way, so my question is really just curiosity. I've learned from reading that a 14.5" barrel with a (longer?) flash suppressor pinned to it allows you to have a shorter barrel without need for a license. However, what's the point? A standard flash suppressor only adds, what, one inch? Why sacrifice an inch and a half of velocity for one inch of length?
:jester:
I went with a pinned 14.5" BCM lightweight upper because I wanted the shortest, lightest upper setup that I could get without having to worry about a tax stamp. I did not plan on having any intentions on changing out the flash suppressor so the fact that its pinned does not make any difference to me. There is little measurable benefit to it but that 1" and a couple ounces is what I was trying to lose for my setup so it was worth it in my opinion.
jonconsiglio
02-11-12, 09:23
Some think there's little difference while some prefer the 14.5", whether pinned or not. I like them both and have both right now. I also have SBR'd lowers.
If I had a quality 16", I wouldn't change it just because I wanted to try a 14.5". If I was buying a new rifle, I'd take it all into consideration.
Just like some guys prefer a 12.5" to an 11.5" or a 10.5" to an 11.5", it's the same for the 14.5" vs 16" stuff. Keep in mind, the difference between a pinned 14.5" and a 16" with standard flash hiders is 1.3". But, some of us use specific muzzle devices for whatever reason, so the difference is often the full 1.5". I'm running A2's now, but will be switching to Surefire flash hiders when my can is ready. I have them sitting here, I just need to install them. On that same note, if you're using the Surefire brakes, the 215a, or one of the AAC blackouts, they add a considerable amount of length and that 14.5" which is normally 16" with the extended flash hider is now 17" (give or take) with something like a Blackout. The 16" is now 18" or 18.5" overall instead of the 17" or 17.3" (or whatever it comes out to) with the A2.
I know what works for me. The only time I need to change anything is when I replace the barrel. I don't change out flash hiders/brakes to try new ones anymore. I put a hand guard of my choice on and stick with it. If something needs fixed on that handguard, I would remove it and send it in. Since only the barrel nut is affected by a perm'd muzzle device, the handguard itself is removable, at least my RIS II's are and my URX's were with the right wrench.
I have an ACOG TA31 RCO with the M4 reticle I run on my 14.5". But, I also run 193, Mk262, TAP 75gr, TSX and others in addition to 855. It works fine and I know the differences from everything from my 10.5" to my SCAR H with the ACOG. So, I can't use that as an argument for the 14.5".
There's nothing wrong with either, though I wouldn't go recommending the pinned 14.5" to a new shooter that may decide to change things once they get to know their rifle a little better.
The velocity loss for a 14.5" from a 16" is pretty small compared to an 11.5" to 10.5". I'd be happy with either if set up correctly, but I can feel a difference in a 14.5" rifle when indoors or in a very thick, wooded area, often suppressed. Well, at least I've convinced myself I can!
I went with a pinned 14.5" BCM lightweight upper because I wanted the shortest, lightest upper setup that I could get without having to worry about a tax stamp. I did not plan on having any intentions on changing out the flash suppressor so the fact that its pinned does not make any difference to me. There is little measurable benefit to it but that 1" and a couple ounces is what I was trying to lose for my setup so it was worth it in my opinion.
I just ordered the same upper for the exact same reasons.
dirt_diver
02-11-12, 12:07
As a resident of Washington, and a non-LEO, I couldn't get a SBR if I wanted to, so the 14.5" is as good as it gets for me, for now...
Living in MA I have no choice but to pin a comp either on a 16,18, 20" so I decided to go as short as I legally could so I went with the 14.5" with BC pinned. As crazy as it sounds to me there is a difference in handling a 14.5" to a 16". It feels a lot shorter even though it's really not that much. If your confident on a muzzle device then go ahead with the 14.5", in the end the pin can be removed by you or a professional.
I've found that a lighter 16" still feels more maneuverable than a heavier 14.5", and as much as I really adore my 14.7" pencil barreled units, I'd still just recommend going with the 16" unless you live in a state that requires a brake to be permanently attached, in which case a 14.5" starts to make sense.
There is an advantage if you can't get an SBR by building a very light 16" OABL unit, but I'd still only consider it after having a running 16" unit for a while (and consider shortening an existing weapon, so that you're not stuck married to a setup you dislike).
Until the Centurion C4FSP rail, I was basically stuck with a less than ideal solution with a pinned 14.7" carbine, and my new-guy itis is still memorialized in a boat anchor SOCOM profiled 14.5" M4A1 type barrel upper that essentially isn't worth the effort to do anything else with.
m1a_scoutguy
02-11-12, 15:40
Living in MA I have no choice but to pin a comp either on a 16,18, 20" so I decided to go as short as I legally could so I went with the 14.5" with BC pinned. As crazy as it sounds to me there is a difference in handling a 14.5" to a 16". It feels a lot shorter even though it's really not that much. If your confident on a muzzle device then go ahead with the 14.5", in the end the pin can be removed by you or a professional.
Well,,,there ya have it,,LOL !!! My reasons "exactly" I like them for the above reason & it makes perfect sense to me (and to my fellow Brothers in Non-Free States) For you guys in Free States its no big deal,,ya can change and swap till your hearts content,,so having a 14.5 could be a pain in the ass so why bother ! It all boils down to,,if ya can save a inch or more and a few ounces or more,,then why not !! I like em,:D,guess thats why I have a 3rd one on the bench now,,,:D but fully understand the reasoning not to have one if you have better options !!! (Laws) ;)
mkmckinley
02-11-12, 15:49
If you're going to do a pinned 14.5" make sure you're getting what you want right off the bat. Once you pin that FH it's a pain to reconfigure.
em_twofourzero
02-11-12, 16:13
FYI, Bravo Company is offering configurations of both their standard and CHF 14.5" uppers, with various brakes/flash hiders pinned to bring them to a legal 16 inches. They also have Surefire MB556K brakes that come "pin ready". Worth checking out IMHO.
I had a 14.5" permed because with the suppressor, I would rather give 1.5" less leverage to that 1# chunk of steel on the end of the barrel.
LowandLeft
02-11-12, 17:57
I got a 14.5 w/ a pinned AAC 51t mostly because of my can. I wanted the rifle as short as possible and I knew I wasn't going to be changing out my muzzle device. Furthermore, I really like the way a 14.5 handles.
Cesiumsponge
02-11-12, 19:31
Lots of folks advocate doing heavy research on your rifle before selecting components. If you do your research, you already know what you like and there is no issue pinning on a 14.5" barrel unless you're the type of person who is always dicking around with things. If you're a tinkerer, then stick with a 16" barrel so you can change things down the road.
I just never understood why people fixated and complained so much about losing a muzzle device on a 14.5" pinned barrel if you wanted to change it. $50-100 in lost muzzle device isn't that much money in the overall game if you're building a top-notch rifle and spending the money on training and ammo.
My BCM lightweight 14.5 with the pinned A2X is my very favorite of my AR's, handy, light and mine seems to be expectionally accurate.
If I could to change anything it would be to have mounted the A2X with a peel washer rather than a crush washer for suppressor mounting.
My next upper will have a BC 2.0 or SF brake with a crusher washer pinned to a 14.5 light weight barrel..
The_War_Wagon
02-11-12, 20:00
Like a LOT of folks, I'm thinking, "I'll go NFA/SBR... ONE of these days"... but THAT day ain't here yet.
What IS here, is my 3 story house, with full basement. That's a LOTTA stairwell to clear, in case of emergency... and every inch COUNTS in it. So that's why I own 2 such rifles.
There are a couple of things that come into play if your going to go with a pinned 14.5" barrel. First like already mentioned is make sure you set it up the way you want. Because you might need a different barrel nut or to remove a delta ring or whatever with some rails you might have to remove the gas block or FSB and in order to do that you need to remove the MD. I think if you go with a mil-spec carbine gas system you should go with the barrel length it was designed for which is 14.5" but YMMV.
arizonaranchman
02-12-12, 14:00
Getting in and out of the rack and in/out of the car it's a noticeable difference believe it or not. My 14.5" BCM feels handier for this than 16" guns I've used in the exact same circumstances.
You guys are confusing the hell out of me.
I thought last year everybody (well at least a few guys) were saying the a mid-length gas system had a "better dwell time" on the 14.5". They had my convinced it was the ideal config.
You guys are confusing the hell out of me.
I thought last year everybody (well at least a few guys) were saying the a mid-length gas system had a "better dwell time" on the 14.5". They had my convinced it was the ideal config.
The issue is 14.5" vs 16" barrels. If relegated to carbine gas systems (e.g., vendors that supply only that config), it makes more sense to go with 14.5" than 16" because the 14.5" was originally designed around this gas system length. But if ML gas is an option, then consider it, along with all the benefits that that system has (accessory mounting ease, smoother cycling, etc.) over a carbine-length gas system.
I'd recommend going with a known vendor that has this figured out and knows how to gas their offerings, whether carbine-length or mid-length. Industry std for 14.5" ports is .062". I suspect ML gas ports may be a tad larger, but I've never seen an industry spec on this config. But by virtually every account, vendors such as DD and BCM have this pretty well nailed.
And I agree it's wise to choose your barrel length based on handiness/maneuverability. If you assume your engagement distance is going to be 75 yards (and that's admittedely an arbitrary number) and in, then I see no downside to the shorter 14.5" barrel. But each individual should decide what's best for their needs.
I don't know what is the ideal dwell time since I'm not an engineer but I can see that if nothing else is considered but dwell time then there are some things that stand out. The distance from the gas hole to the end of the A2 flash hider on a 20" barrel with rifle length gas system is about 7.5." The 16" barrel with mid-length gas system is about 7.5" the 14.5" barrel with carbine-length gas system is about 7.5."
The way I understand it also is there are no set gas port diameters for anything other than a Carbine and Rifle length gas system. Now I wouldn't hesitate to buy a Noveske with a midlength and I haven't had any problems with my MRP I think as long as you don't buy crap you'll be GTG
jonconsiglio
02-12-12, 18:00
Personally, I like the mid length gas system on the 16" and so far it's good for me on a 14.5", but I pretty much only run 5.56 ammo.
I think the carbine/mid length thing is a bit overhyped. I have a 14.5" BCM mid length with a RIS II. Forum member samuse has a Colt 14.5" with a carbine gas system. Side by side with 855, I could hardly tell a difference. It was there, but not nearly like some make it sound. We put a Vltor A5 on his and the difference was almost none.
My Colt 16" with the Vltor A5 is also pretty similar. Don't get me wrong, I can see a difference, but it's nowhere near the main deciding factor for me. I'd be perfectly happy with either for a 14.5" and won't be running out to sell a 16" with a carbine gas as long as it's from a company like Colt that uses the proper gas port.
If I was running full auto regularly, then I'd certainly prefer the mid length as I've found I can keep about 1/3rd more rounds on target before they walk.
There are other things besides that recoil that matter the most to me. Will I be using a FSB? If so, do I want to mount anything in front of it, or would I prefer a longer sight radius? For me, if I'm keeping the FSB, I'll probably opt for the mid length. If I'm going with a low pro gas block, then I'll choose manufacturer and accuracy of the barrel first. Then, if they offer both, I'll decide from there based on others' experiences that I trust.
Some, you won't even have the option. Colt, for now, is only carbine. Centurion and Noveske, for example, only have the mid length listed for their 14.5" and 16" barrels. I know Noveske offers the carbine gas system as well, at least on the 14.5", but it's a special order item and not listed.
I can almost guarantee that if I handed 10 shooters two properly configured rifles with the appropriate buffers and gas ports set up the same and using the same ammo, at least 3/4 of them wouldn't be able to pick the mid length from the carbine.
EDIT - I'll admit I bought into the mid length gas system as being a bigger deal than it really is at first. Now I see things more clearly and will be happy either way as long as it's made by a quality manufacturer.
The issue is 14.5" vs 16" barrels. If relegated to carbine gas systems (e.g., vendors that supply only that config), it makes more sense to go with 14.5" than 16" because the 14.5" was originally designed around this gas system length.
I'm fairly sure the carbine-length gas system was designed around the shorter 11.5" CAR-15 / XM-177 barrels, not the 14.5" barrels of the M4.
-B
I personally don't think the extra time the bullet has to travel from gas port to muzzle in the 16" and the 14.5" carbine matters much, if at all. That is a mere 1.5" and the difference in time between the two is .042 milliseconds. That is less than 5/100,000 of a second. How can the gases in that short time cause the movement of the bolt carrier group to be more violent when bullet has cleared the muzzle by several feet before the BCG even begins to move?
To create the pressures generated by a modern rifle cartridge, even in such a small space as a rifle bore requires high volume of gas and it takes time for that volume of gas to vent into the atmosphere after the bullet has exited. What the extra distance between the 16" and 14.5 inch barrel does is increase the time needed for the gases to vent. That's why rifles running suppressors are over-gas- not because it increases the time needed for the bullet to clear the muzzle but because they act as a pressure reservoir that increases the time needed to vent the gases.
Over pressurization isn't the result of increased dwell time of the bullet travelling from the gas port to the muzzle, but from increasing the time needed for the system to depressurize after the bullet has exited
cankicker01
02-12-12, 19:44
I know the conversation has steered toward the tech. end. But I'm about to cop a Noveske 14.5 that is pinned with a surefire flash suppressor, for a can. I live in the very NE corner of Georgia and don't want to go full blown sbr because I have friends over the line in NC and SC don't want to have to do paperwork just to go see buddies.
When I bought my 14.5 w/pinned A2X, I wanted the most compact and light set up I could. SBR is not an option for me.
It fit the purpose of the rifle I was putting together. That's why I got it. No other reason. I think we tend to over think things here.
What's the desired purpose of the rifle? Build to that purpose and you'll be happy.
Doc Safari
02-12-12, 23:53
I got a pinned 14.5" lightweight upper because Bravo Company was quoting several months wait on the 16" lightweight upper. Other than that I probably would have gone with the 16".
polymorpheous
02-13-12, 03:21
Is there a significant weight difference between a 16" and 14.5"?
jonconsiglio
02-13-12, 03:43
Is there a significant weight difference between a 16" and 14.5"?
I think it's something like 2 ounces. If I remember correctly (at 3am) it basically splits the difference between a standard and lightweight 16", or pretty close.
Is there a significant weight difference between a 16" and 14.5"?
On a scale, no. But when handling it, you can tell the difference since the weight is at the extreme end of the barrel.
You would need a shot timer to determine if it "makes" a difference. However, my next build will be a 14.5" since I like the feel, prefer as short as possible(without stamp right now) and have no need for the extra barrel length.
For a first gun, I would suggest 16". Preferably midlength. FWIW the carbine was designed around the 11.5" barrel. The 14.5" barrel was an after thought and caused problems hence the extrapower extractor.
If you're not planning on attaching a suppressor then a 14.7 w/ pinned battlecomp 1.0 is a great option and what I would run in carbine courses or 3 gun. If you are planning on attaching an m42000 or such, a 14.5 with a pinned AAC brakeout is the way I would go.
If you're not planning on attaching a suppressor then a 14.7 w/ pinned battlecomp 1.0 is a great option and what I would run in carbine courses or 3 gun. If you are planning on attaching an m42000 or such, a 14.5 with a pinned AAC brakeout is the way I would go.
Why not just use a BC 1.5 with a 14.5" standard length barrel? Or just get a 14.5" with the A2X from BCM and save yourself a bundle.
On a scale, no. But when handling it, you can tell the difference since the weight is at the extreme end of the barrel.
You would need a shot timer to determine if it "makes" a difference. However, my next build will be a 14.5" since I like the feel, prefer as short as possible(without stamp right now) and have no need for the extra barrel length.
For a first gun, I would suggest 16". Preferably midlength. FWIW the carbine was designed around the 11.5" barrel. The 14.5" barrel was an after thought and caused problems hence the extrapower extractor.
The carbine gas system was originally designed for a 11.5" barrel as in the XM177. But during later testing, the USMC found that the gas port needed to be farther from the muzzle of the barrel to increase reliability and ended up with the 14.5" and the M4.
OP, there's a only a couple reasons I could see for getting a 14.5". The first being weight savings if you go with a light weight profile and the other being traditionalism as far as an m4 copy goes. The length savings is pretty minimal considering that you have pin and weld an extended fh/comp since theres a lot of shorter fh/comps you could put on a 16"
For the most part, more people will be better off with a 16" barrel just for the ease of fh/comp change and the small advantage in velocity. That being said my first AR was a 14.5" and I doubt I'll ever get rid of it for a 16" just for velocity advantage.
I'm about to buy a BCM lw 14.5" middy for a build for my tiny gf to train with. I would like to teach her to shoot better but my standard 16" middy is to heavy for her to run effectively.
I'm just hoping that with the lost weight it shoots near as smooth as my 16". I would really like her to be comfortable with the gun.
I'm about to buy a BCM lw 14.5" middy for a build for my tiny gf to train with. I would like to teach her to shoot better but my standard 16" middy is to heavy for her to run effectively.
I'm just hoping that with the lost weight it shoots near as smooth as my 16". I would really like her to be comfortable with the gun.
I think you're talking about a 2 ounce difference at the most; even less if you have it pinned out to 16"...
Why not just use a BC 1.5 with a 14.5" standard length barrel? Or just get a 14.5" with the A2X from BCM and save yourself a bundle.
I would rather have the extra .2" in barrel length rather than an extra .2" on a BC1.5 that is no more effective than a BC1.0. I understand that an extra .2" will make only a minute difference if any at all, however I like to squeeze out the most performance out of any application. Plus, 14.7 middys are not expensive (note I am not promoting psa, just making a point): http://www.palmettostatearmory.com/2541.php
I think you're talking about a 2 ounce difference at the most; even less if you have it pinned out to 16"...
Not so much weight as it is leverage. Especially if you run a can on the end of it.
Even though my rifle sits in a cruiser every day, it's encased in a trunk. So I just went with a 16" BCM because they were in stock and cheaper. I didn't feel like waiting weeks/months and paying extra for something that didn't really benefit me.
wild_wild_wes
02-14-12, 14:46
The carbine gas system was originally designed for a 10.0" barrel as in the XM177 :smile:
I'm suspicious of the origin of the 14.5" length, because it duplicates the A1 configuration, and allows attachment of the bayonet.
The carbine gas system was originally designed for a 10.0" barrel as in the XM177 :smile:
I'm suspicious of the origin of the 14.5" length, because it duplicates the A1 configuration, and allows attachment of the bayonet.
that might be why they went with 14.5" and carbine gas. Carbine gas is not optimal for 14.5". Midlength is optimal for between 14.5 and 16" It would take some proof to convince me the carbine/14.5" bbl was chosen for its "optimal" performance... then again it wouldt be the first time a study found the wrong info... Im not saying its a huge performance difference, but I was under the impression convenience was the reason for the combo. I couldt find any data from google either way.
Midlength is optimal for between 14.5 and 16"
based on what?
nineteenkilo
02-14-12, 16:17
Carbine gas is not optimal for 14.5". Midlength is optimal for between 14.5 and 16" It would take some proof to convince me the carbine/14.5" bbl was chosen for its "optimal" performance...
You are aware the Colt 6920 (the sort of accepted standard against which others are measured) uses a carbine gas system with a 16"" bbl? I will give that the midlength has been perceived to be smoother by some, but I don't believe there is any empirical data to support it running any better. I'm with you - if it's out there, I can't find it. :moil:
based on what?
The original gas to barrel ratio on the AR15. I'm not sure there is any other data about that.
jonconsiglio
02-14-12, 17:48
I've said this already but it's worth repeating. I own a number of rifles, one of my most reliable is a 14.5" mid length. I also own a 16" carbine (Colt). The differences are so small between properly set up rifles that it's almost a waste of time to argue about it.
The only thing optimal for me is a rifle I can pick up and it works. I bought into the hype at first when the mid length started getting more attention. I see where it has some benefits, but nothing that would make me switch anything out.
I seriously doubt we would be hearing all of these glowing reports on reliability of rifles, whether carbine or mid length, if there was something wrong with the system. There's nothing wrong with publicly stating a preference based on personal experience AFTER owning both and giving them a serious workout, but some of the arguing I've seen (and even taken part in) is a bit over the top.
The other day I shot a 14.5" mid length BCM back to back with a 14.5" carbine and I hardly noticed any difference. Hell, I'd take a Colt 16" carbine over something like a Rock River 14.5" over gassed mid length. I'm all for slightly softer shooting while still being reliable, I just think some people imagine some sort of advantage that barely shows on a flat range let alone when there are other things going on.
Buy from a reputable manufacturer and set it up the way it works best for you, the shooter (generally speaking).
that might be why they went with 14.5" and carbine gas. Carbine gas is not optimal for 14.5". Midlength is optimal for between 14.5 and 16" It would take some proof to convince me the carbine/14.5" bbl was chosen for its "optimal" performance... then again it wouldt be the first time a study found the wrong info... Im not saying its a huge performance difference, but I was under the impression convenience was the reason for the combo. I couldt find any data from google either way.
You have to remember that it's been quite a while since then. Not too long before that doctor's were saying that cigarettes were healthy for you.
Carbine and midlength is a pretty oveblown argument. If it wasn't for oversized gas ports on lower quality carbines we might not even have as much to argue about.
lifebreath
02-14-12, 23:34
based on what?
I recall reading some material about this as well. Here's one quote from an "Ask Mike Pannone" thread (https://www.m4carbine.net/showthread.php?t=97540):
"The advent of the middy was an attempt to match the gas system to the barrel length which was originally a problem with the civilian 16" barreled guns with the 7.5" gas system and a port drilled for the 14.5”. The addition of 1.5" from the military configuration (14.5"bbl>7.5"tube) over-gassed an already over-gassed design. The 14.5 over gassing was by design for reliability under adverse combat conditions. The 16" over-gassing on top of that was an oversight and a desire to use existing tooling and parts."
Interestingly, the mid-gas system on the KAC SR-15 16" barrel is a little longer than the mid-gas system on a BCM 14.5" barrel. I suspect this is due to the attempt fine-tune the gas pulse peak pressure and timing. Also, the port size will effect the pressure curve envelope over time, since the rate at which gas flows into the tube and bolt will be influenced.
I have both of these guns and definitely prefer both to my 16" carbine gas guns (Colts). My 14.5" with permed A2 is my #1 go-to gun and is set up for HD. It just handles differently than a 16" gun and it balances out better with a Surefire on the end.
However, it's splitting hairs. I'd easily grab my 6920 in a pinch and feel quite satisfied.
Well, I think 14.5" middy is optimal because I bought one. That means its the best.
Seriously, though, I don't know where people get off thinking that you need all that barrel down-stream of the port for the rifle to be reliable. My 14.5" Noveske middy will fire XM193, cycle the action, and feed another shell, with the switchblock in the "Suppressed" position with no can on it. It won't lock back on an empty mag, but still, with HALF! the gas-port size roughly, it's STILL cycling with XM193. That tells me there is PLENTY of barrel past that port that reliability is not a concern.
I've said this already but it's worth repeating. I own a number of rifles, one of my most reliable is a 14.5" mid length. I also own a 16" carbine (Colt). The differences are so small between properly set up rifles that it's almost a waste of time to argue about it.
The only thing optimal for me is a rifle I can pick up and it works. I bought into the hype at first when the mid length started getting more attention. I see where it has some benefits, but nothing that would make me switch anything out.
I seriously doubt we would be hearing all of these glowing reports on reliability of rifles, whether carbine or mid length, if there was something wrong with the system. There's nothing wrong with publicly stating a preference based on personal experience AFTER owning both and giving them a serious workout, but some of the arguing I've seen (and even taken part in) is a bit over the top.
The other day I shot a 14.5" mid length BCM back to back with a 14.5" carbine and I hardly noticed any difference. Hell, I'd take a Colt 16" carbine over something like a Rock River 14.5" over gassed mid length. I'm all for slightly softer shooting while still being reliable, I just think some people imagine some sort of advantage that barely shows on a flat range let alone when there are other things going on.
Buy from a reputable manufacturer and set it up the way it works best for you, the shooter (generally speaking).
Good post.
I'm working on an "if it ain't broke, don't fix it" article where I'm also discussing deviating from the norm or the ubiquitous and the anachronists that insist on doing so.
The single benefit of the mid-length that can be seen/proven to date is that the front sight is further from the rear sight. "Reduced recoil" hasn't been proven. "Reduced parts wear" hasn't been proven. So that leaves longer sight radius and longer handguard. And with the ever-increasing trend of shaving down the FSB and installing a 12"+ rail, and the ever-increasing relegation of iron sights to backup status, even those benefits are falling by the wayside.
I don't own a mid-length anything myself anymore, but I have three BCM mid-lengths here for T&E. I'm not opposed to them but I don't think they cure cancer either.
Interestingly, the mid-gas system on the KAC SR-15 16" barrel is a little longer than the mid-gas system on a BCM 14.5" barrel. I suspect this is due to the attempt fine-tune the gas pulse peak pressure and timing. Also, the port size will effect the pressure curve envelope over time, since the rate at which gas flows into the tube and bolt will be influenced.
Little side-track here...
The KAC gas tube is just their .308 tube. It was a part they had in-stock and on-hand and didn't require manufacturing a new part. Gas port was subsequently sized to work with the tube. The system was not designed from scratch in a vacuum to be "optimal".
I think this exemplifies the danger in all of this. People reverse-engineer things in their minds and make assumptions based on existing product. As much as we'd all like to think that a team of engineers designs every single thing (hopefully with the overwatch of actual shooters, otherwise you wind up with a lot of WTF) from scratch in a vacuum for "optimal" function, it just doesn't happen and everyone's version of "optimal" is different.
Look at the Pannone quote. the 14.5" was intentionally over-gassed (I'd still like to see a source for that claim) to better guarantee reliability. So what's "optimal", the guy shooting 200 rounds from a bench a year "feeling less recoil" or the Soldier or Marine having a gun that will run longer?
Good post.
I'm working on an "if it ain't broke, don't fix it" article where I'm also discussing deviating from the norm or the ubiquitous and the anachronists that insist on doing so.
The single benefit of the mid-length that can be seen/proven to date is that the front sight is further from the rear sight. "Reduced recoil" hasn't been proven. "Reduced parts wear" hasn't been proven. So that leaves longer sight radius and longer handguard. And with the ever-increasing trend of shaving down the FSB and installing a 12"+ rail, and the ever-increasing relegation of iron sights to backup status, even those benefits are falling by the wayside.
I don't own a mid-length anything myself anymore, but I have three BCM mid-lengths here for T&E. I'm not opposed to them but I don't think they cure cancer either.
My mid-length Noveske allows for better placement of the switchblock. (with a carbine-length, rail-space would be compromised)
I like to think erosion of the gas-port is less, the further it is from the chamber. I can't prove it, but I don't think many would disagree on principal.
I have not had any trouble with my middy.
My mid-length Noveske allows for better placement of the switchblock. (with a carbine-length, rail-space would be compromised)
I like to think erosion of the gas-port is less, the further it is from the chamber. I can't prove it, but I don't think many would disagree on principal.
I have not had any trouble with my middy.
I'm starting to think you were serious here
Well, I think 14.5" middy is optimal because I bought one. That means its the best.
You don't have to defend your purchase. If it works for you just be happy with it. I'm not against the mid-length I just haven't seen any actual evidence of any benefits other than the obvious dimensional one (such as your concern over placement of your Switchblock). Just a lot of "most would agree", "it seems to me", "I like to think" and other "principals". :p
I'm starting to think you were serious here
You don't have to defend your purchase. If it works for you just be happy with it. I'm not against the mid-length I just haven't seen any actual evidence of any benefits other than the obvious dimensional one (such as your concern over placement of your Switchblock). Just a lot of "most would agree", "it seems to me", "I like to think" and other "principals". :p
Well, it seems to me, and I bet most would agree, that it works just fine, and I would like to think that that is the principal of the matter. ;)
Well, it seems to me, and I bet most would agree, that it works just fine, and I would like to think that that is the principal of the matter. ;)
No, it's not. It is part of the matter. Maybe.
If you're going to deviate from the norm you better get some kind of tangible benefit from it. Different isn't better, better is better.
ETA:
before this gets out of hand...
I'm not bashing you, your choice, etc. or anyone else that chooses a mid-length. I don't care what someone else shoots. I'm just hoping to spark some discussion, but in order to do that people are going to have to be able to be dispassionate about their choices and discuss things rationally.
Will a 14.5" mid-length run? Of course it will. I have something like 1k+ rounds of low-powered steel-cased ammo through a couple of them, combined. That's not what I'm questioning.
No, it's not. It is part of the matter. Maybe.
If you're going to deviate from the norm you better get some kind of tangible benefit from it. Different isn't better, better is better.
ETA:
before this gets out of hand...
I'm not bashing you, your choice, etc. or anyone else that chooses a mid-length. I don't care what someone else shoots. I'm just hoping to spark some discussion, but in order to do that people are going to have to be able to be dispassionate about their choices and discuss things rationally.
Will a 14.5" mid-length run? Of course it will. I have something like 1k+ rounds of low-powered steel-cased ammo through a couple of them, combined. That's not what I'm questioning.
Pressure charts have already been posted ad nauseum, and you yourself say it runs reliably, with slightly less recoil. Why not embrace it?
Pressure charts have already been posted ad nauseum,
they have?
and you yourself say it runs ... ...with slightly less recoil.
I have?
If so, I'm reversing myself, because I have not shot two otherwise identical guns, with only a gas-system length in difference between them, to be able to say that, and if I did say it then I did so entirely prematurely. and even then it's nothing more than a mk1-mod0 shoulder test.
Until someone performs a test with two identical guns with an accelerometer present to measure the forces at play, nobody can empirically state that there is any difference in recoil.
I know the conversation has steered toward the tech. end. But I'm about to cop a Noveske 14.5 that is pinned with a surefire flash suppressor, for a can. I live in the very NE corner of Georgia and don't want to go full blown sbr because I have friends over the line in NC and SC don't want to have to do paperwork just to go see buddies.
You only need to do the paperwork once a year if you specify a 12mos period
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cankicker01
02-15-12, 09:11
Wahoo, thanks for the info. I need to read the fine print next time. I will def. check into that. "in all your getting, get understanding.".
Doc Safari
02-15-12, 09:29
Well, I think 14.5" middy is optimal because I bought one. That means its the best.
LOL! Even though you're joking you've "outed" the real reason a lot of people argue in favor of any configuration.
I have a friend who owns registered NFA M16's, SBR's, and has built his own AR's. He understands optimizing performance for certain ammo, buffers, gas port sizes, and whatnot. He could maybe be considered a "subject matter expert" at least by local standards.
His reason for preferring the 14.5" mid-length over a 16" carbine? He thinks the 16" looks "ugly" with that extra barrel sticking out. :lol:
based on what?
Based on gas pressure and dwell time charts that show the 14.5 and 16" midlengths having operating data close to that of a 20" rifle while the carbine was a much sharper, higher peak. Again I'm not saying this is "better", as with a properly set up m4, its fine. However when you combine operating conditions of a 16" carbine, with the buffer and gas port size that were designed around the 10" or 11" barrel, you have problems. The mids I shot were smoother than my carbine allowing faster followups, so my next gun will be a mid gas. People prefer different things for different reasons, if its well made and reliable, you are good to go.
Maybe that data was wrong, or tweaked for the posters interest, I dont know, but thats what the data I found showed.
here is the chart I found from http://smctacticalnc.blogspot.com/2011/12/part-one-thoughts-on-what-to-look-for.html
http://2.bp.blogspot.com/-EFHqHPFZQ_A/Tt6cInNysxI/AAAAAAAAAa0/DCUWP-NAEkU/s1600/223plot.gif
Anyway, as for the OP, some people (me included) have no use for the extra bbl length. If there was no NFA laws, I'd have a 11.5 or 12.5", but 14.5 permed is the shortest possible, and you can get a comp or a good flash hider (or a combo of them) on there too. For me, there is a difference in the feel of the gun, but I would have to get on a timer to know if its better or not. However, its a lot more comfortable moving around a house with and inch off the gun. It makes more difference than it sounds, for me anyway.
If you are confident with you're purchase and perform well with it, then it doesnt matter.
What I don't get is why people with legitimate concerns about length don't just put a thread protector on their muzzle and forget about the flash hider. It's not like it's blindingly bright or anything.
It's not like it's blindingly bright or anything.
Yeah....flash is no issue at all
http://i210.photobucket.com/albums/bb244/a996hawk/68067_155300277842852_154796331226580_261411_4833199_n-1.jpg
http://i210.photobucket.com/albums/bb244/a996hawk/223759_10150734933255123_619200122_19721828_767824_n.jpg
What I don't get is why people with legitimate concerns about length don't just put a thread protector on their muzzle and forget about the flash hider. It's not like it's blindingly bright or anything.
It could be at night, particularly inside houses where many folks use thier AR for home defense. There are also quite a few military and law enforcement people on the forum who have a lot of good reasons to have that flash as suppressed as possible. Some flash hiders and other end-of-barrel candy also helps redirect some of that flash in directions that reduce muzzle climb or felt recoil ever so slightly. There are lots of reasons to have a muzzle device on.
BUT if you dont want one, you certainly dont need one.
lifebreath
02-15-12, 10:37
His reason for preferring the 14.5" mid-length over a 16" carbine? He thinks the 16" looks "ugly" with that extra barrel sticking out. :lol:
I agree and must admit that is a factor for me! My BCM 14.5" middy just looks cool. I would not choose form at the expense of function, but if two things perform equally well, I prefer the one that looks best. So, while my 14.5 middy looks cool, it also performs flawlessly and feels better in my hands than my other ARs. It is also more accurate than my other ARs.
Rob - while you argue for dispassion and objectivity, there is a place for passion and subjectivity. Certain subjective impressions can help a person's performance with a given tool. For example, many hammers will drive a nail into a board well. However, a certain hammer may feel to one carpenter and he is able to hammer more effectively with it, while another carpenter prefers a different hammer. One person shoots better with an Aimpoint, another with an EOTech, etc. We may even be passionate about our choices. As long as our passion is tempered by sound judgment, informed by reason and we are not driven by passion to the exclusion of such, our passion serves us as we wish and often propels us forward in a way that dispassion cannot.
I would hazard a guess that many on this forum are very passionate about weapons, warfare, shooting, etc., and this passion provides motivation to learn, improve our skills and hold these incredibly informative discourses.
Now, to the OP's original question, I do see some advantage to a pinned 14.5" vs. a 16" with muzzle device. I was moving around the house last night with both weapons. The slightly shorter barrel was just a little more maneuverable. Our kinesthetic sense never ceases to amaze me - how finely tuned it is. An inch or two may not seem like it should matter (insert size joke here), but it can make a big difference. I collect watches and the difference between a larger, thicker watch and a small thin watch is the difference between banging the watch on door jambs and doorknobs or not. That's a difference of a few millimeters.
Also, the slightly less weight out front (reduced moment of inertia) does make a difference (assuming similar barrel profiles).
These are my subjective impressions.
I was thinking last night that I would love to do a scientific test as Rob described, eliminating as many variables as possible and isolating the gas system's impact on recoil impulse. I would not only want to measure the peak force, but the whole recoil impulse over time (its dynamic envelope). To take it a step further, one could then have a significant number of subject shoot the guns and attempt to correlate objective performance and subjective impressions with the two gas systems.
Would anyone like to provide me guns and ammo for the study? :D
FYI, Bravo Company is offering configurations of both their standard and CHF 14.5" uppers, with various brakes/flash hiders pinned to bring them to a legal 16 inches. They also have Surefire MB556K brakes that come "pin ready". Worth checking out IMHO.
Please post an example. I cant find one.
they have?
I have?
If so, I'm reversing myself, because I have not shot two otherwise identical guns, with only a gas-system length in difference between them, to be able to say that, and if I did say it then I did so entirely prematurely. and even then it's nothing more than a mk1-mod0 shoulder test.
Until someone performs a test with two identical guns with an accelerometer present to measure the forces at play, nobody can empirically state that there is any difference in recoil.
I thought they had, and I thought you did. Hold for source.
Wait: I see someone already posted the data for us, now let me go find your post.
I agree and must admit that is a factor for me! My BCM 14.5" middy just looks cool. I would not choose form at the expense of function, but if two things perform equally well, I prefer the one that looks best. So, while my 14.5 middy looks cool, it also performs flawlessly and feels better in my hands than my other ARs. It is also more accurate than my other ARs.
Rob - while you argue for dispassion and objectivity, there is a place for passion and subjectivity. Certain subjective impressions can help a person's performance with a given tool. For example, many hammers will drive a nail into a board well. However, a certain hammer may feel to one carpenter and he is able to hammer more effectively with it, while another carpenter prefers a different hammer. One person shoots better with an Aimpoint, another with an EOTech, etc. We may even be passionate about our choices. As long as our passion is tempered by sound judgment, informed by reason and we are not driven by passion to the exclusion of such, our passion serves us as we wish and often propels us forward in a way that dispassion cannot.
I would hazard a guess that many on this forum are very passionate about weapons, warfare, shooting, etc., and this passion provides motivation to learn, improve our skills and hold these incredibly informative discourses.
Now, to the OP's original question, I do see some advantage to a pinned 14.5" vs. a 16" with muzzle device. I was moving around the house last night with both weapons. The slightly shorter barrel was just a little more maneuverable. Our kinesthetic sense never ceases to amaze me - how finely tuned it is. An inch or two may not seem like it should matter (insert size joke here), but it can make a big difference. I collect watches and the difference between a larger, thicker watch and a small thin watch is the difference between banging the watch on door jambs and doorknobs or not. That's a difference of a few millimeters.
Also, the slightly less weight out front (reduced moment of inertia) does make a difference (assuming similar barrel profiles).
These are my subjective impressions.
I was thinking last night that I would love to do a scientific test as Rob described, eliminating as many variables as possible and isolating the gas system's impact on recoil impulse. I would not only want to measure the peak force, but the whole recoil impulse over time (its dynamic envelope). To take it a step further, one could then have a significant number of subject shoot the guns and attempt to correlate objective performance and subjective impressions with the two gas systems.
Would anyone like to provide me guns and ammo for the study? :D
This study has already been done, and it proves my point about the mid-length. These are 3-rounds fired full auto. They clearly show the 6933 cycling faster. If it's cycling faster, it's slinging things faster. Those things (A bcg) weigh the same. The faster they move, the more recoil they create. Physics tells us that the mid-length recoils less, and my shoulder agrees. My Noveske is much smoother/lighter than other carbines I have shot.
Noveske 14.5 w/Switchblock:
http://i135.photobucket.com/albums/q153/hootiewho6933/Scar/SBNorSetting.jpg
Colt 6933 w/H2 Buffer:
http://i135.photobucket.com/albums/q153/hootiewho6933/Scar/H2copy.jpg
tdc rangemaster
02-16-12, 22:16
I Have a 14.5 and really like the looks and function of it. it feels shorter and faster, which I like. I also have a 16 inch which I dont like quite as much but its not a huge deal for me. If i was going to order a new upper dependant on mission I would chose the shorter pinned barrel again. My friend feels differently and prefers a 16 inch. I think its mostly just a preference.
I Have a 14.5 and really like the looks and function of it. it feels shorter and faster, which I like. I also have a 16 inch which I dont like quite as much but its not a huge deal for me. If i was going to order a new upper dependant on mission I would chose the shorter pinned barrel again. My friend feels differently and prefers a 16 inch. I think its mostly just a preference.
Something noone has mentioned yet is that my suppressor mount will NOT shoot loose and cause me a baffle strike. Something that happened to another poster either here, or on TOS a while back, Rockset not withstanding.
This study has already been done, and it proves my point about the mid-length. These are 3-rounds fired full auto. They clearly show the 6933 cycling faster. If it's cycling faster, it's slinging things faster. Those things (A bcg) weigh the same. The faster they move, the more recoil they create. Physics tells us that the mid-length recoils less...
Not when the input of energy is the same. The gas system does not change how much recoil the cartridge generates. The moving parts do not generate more recoil because it takes energy to get them moving in the first place. What they change is the profile of the recoil impulse and how it's distributed
Not when the input of energy is the same. The gas system does not change how much recoil the cartridge generates. The moving parts do not generate more recoil because it takes energy to get them moving in the first place. What they change is the profile of the recoil impulse and how it's distributed
I understand what you are saying, but let me word it this way. I can rep out with a bar and some plates on the flat-bench, moving the bar a few feet up and down in a controlled manner. Now, if I were to try and CATCH the bar as someone dropped it from 2 feet up...well...that would suck.
Now, you have a rifle and a shoulder.
Total energy may not matter, but that recoil impulse as you noted has a direct correlation on how the weapon and shooter deal with that energy.
I understand what you are saying, but let me word it this way. I can rep out with a bar and some plates on the flat-bench, moving the bar a few feet up and down in a controlled manner. Now, if I were to try and CATCH the bar as someone dropped it from 2 feet up...well...that would suck.
Now, you have a rifle and a shoulder.
Total energy may not matter, but that recoil impulse as you noted has a direct correlation on how the weapon and shooter deal with that energy.
Good example. The amount of energy remains the same in both scenarios but how it's transferred to your arms is different. One is a sudden stop (deceleration) after acceleration. The other has energy being directed against the acceleration vector to spread the deceleration over a longer time. Same amount of energy, different profiles
Good example. The amount of energy remains the same in both scenarios but how it's transferred to your arms is different. One is a sudden stop (deceleration) after acceleration. The other has energy being directed against the acceleration vector to spread the deceleration over a longer time. Same amount of energy, different profiles
So, in short, I will rep out with my middy and let the other guys catch the bar with their carbine-length gas systems.
In all seriousness, though, the reason I like the middy is because I plan on running it suppressed. Now, I know that the switchblock on my rifle is a good thing, but the fact that the bullet will spend 1.5 inches less in the barrel (and hence in the suppressor...) after passing the gas-port makes me think that this will IN SOME MINUTE WAY cut down on the influence of running a can on weapon-timing, allowing chamber pressure to drop just that much more before extraction begins.
Minute? Insignificant?
Well since I started from scratch, "free" was a good price-difference to pay between "none" and "maybe a minute amount" of benefit.
Living in MA I have no choice but to pin a comp either on a 16,18, 20" so I decided to go as short as I legally could so I went with the 14.5" with BC pinned. As crazy as it sounds to me there is a difference in handling a 14.5" to a 16". It feels a lot shorter even though it's really not that much. If your confident on a muzzle device then go ahead with the 14.5", in the end the pin can be removed by you or a professional.
Same here...
Living in NJ the ability to remove a muzzle device from a 16" and longer barrel at any time does not apply as all muzzle devices must be permanently attached. So I may as well get a 14.5".
lifebreath
02-17-12, 11:09
I understand what you are saying, but let me word it this way. I can rep out with a bar and some plates on the flat-bench, moving the bar a few feet up and down in a controlled manner. Now, if I were to try and CATCH the bar as someone dropped it from 2 feet up...well...that would suck.
Now, you have a rifle and a shoulder.
Total energy may not matter, but that recoil impulse as you noted has a direct correlation on how the weapon and shooter deal with that energy.
Correct and good analogy. People confuse energy, force, power and work. A sharp blow of a hammer to a nail imparts a great amount of energy to the nail over a very short time period, creating the force and power to drive it in (work). A child pushing his finger against the nail as hard as he can for 8 hours may expend a greater amount of total energy but will never create enough force to move the nail.
A fast, sharp recoil impulse transmits the same energy in a shorter period, creating a greater force, which drives the shoulder back more violently than a longer, smoother recoil impulse. The longer recoil impulse imparts the same energy over a longer period with less force against the shoulder. This should translate into greater control with more ease and less fatigue.
I went with a 14.5 with 1.5 Battle Comp on my Bravo because it's what I wanted. Can't say I had a real reason for this other than it's what I liked and wanted.
try lugging around a 20" rifle at work clearing a large building and you'll see why shorter is better. it depends on what you want to do with it.
for me, the 20" is too long, we converted a bunch of them to 16" carbines (i wanted to do shorter midlength, but got voted out). and it fits our chargers better, no way were the 20" rifles going to fit. we got our rifles from the military.
i built a 14.7" with a pinned flash hider making it the legal length, it is a midlength setup, shoots much nicer than our 16" ones and is easier to get in and out of the car (well, i have a collapsible stock on mine, the city rifles still have the ancient a2 stocks, no money).
ROUTEMICHIGAN
02-18-12, 01:28
14.5" middy lightweight barrel with BC 1.5 pinned for me. Also have a 16" carbine length. Love 'em both, but the 14.5" has been the one going into the Pelican case for training. The combination of the shorter and lighter barrel with the longer handguard -- for me-- makes this gun more maneuverable than the 16" gun. I run the middy (and carbine) with an H2 buffer with blue Sprinco spring-- perfect. As others here have said, 1" doesn't seem like a huge difference-- but after long and numerous training evolutions that involve dynamic movement, I appreciate the lighter/shorter barrel. Especially as an old guy!
It doesn't make much sense unless you actually use the weapon in ways that it matters. If you are a bench shooter, 16, 18, 24 or whatever is all a moot point. If you are a cop who is pulling it out of your cruiser, or clearing buildings, you will see and feel a difference.
The other reason is also pretty simple, its just because you want to. Modern rails allow you to install what you want, and if you can't figure out what muzzle device you need, then stick with a 16".
Good advice. I have a 14.5 cause it looks better to me, balances better and is handier. An inch doesn't seem like much until you start using it.
It's your rifle, do what you want.
This study has already been done, and it proves my point about the mid-length. These are 3-rounds fired full auto. They clearly show the 6933 cycling faster. If it's cycling faster, it's slinging things faster. Those things (A bcg) weigh the same. The faster they move, the more recoil they create. Physics tells us that the mid-length recoils less, and my shoulder agrees. My Noveske is much smoother/lighter than other carbines I have shot.
Noveske 14.5 w/Switchblock:
http://i135.photobucket.com/albums/q153/hootiewho6933/Scar/SBNorSetting.jpg
Colt 6933 w/H2 Buffer:
http://i135.photobucket.com/albums/q153/hootiewho6933/Scar/H2copy.jpg
apples and orangutans. But either you know this and are posting this nonsense anyway, or you don't and pointing it out isn't going to change anything.
ETA:
where did you get those images? common practice is to cite one's source.
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