14.5 inch barrel: carbine or middy?

[Javang13]

I'm getting ready to build my next AR and am trying to decide between a carbine length or mid-length gas system for a 14.5 inch barrel. I've heard some great things about the middy setup but I know that a 14.5 in barrel was designed for the carbine length gas system. Is their an advantage to one setup over the other? Either way i'm planning on using a DD M4 12.0 FSPM rail. Thanks for the input!

[Quentin]

Midlength 14.5s are getting a lot of great reviews over the last year. I think the only down side could be short stroking with low power ammo like Wolf/Tula/etc. steel case. Even that can be tuned out most likely.

[todd.k]

Picking a QUALITY barrel is much more important than the difference in gas system. I'd pick the mid between two barrels of equal quality.

Also note the carbine gas system was designed for the 10" barreled Colt 607 "submachine gun" not for the 14.5" barrel length.

[TehLlama]

I'd go straight up DD V5 upper at that point - 12" Rail, Middy. Why a 14.5" over a 16"?

[Javang13]

I want the 14.5 simply because its shorter. I know its not much but i think the 14.5 balances a little better. Also, the optic that I will use is calibrated to a 14.5 inch barrel. Thanks for your input everyone i think i'm going to get the middy!

[AR-10]

I made the mistake of pinning a flash hider to my one and only 14.5" barrel.

After that particular build, I will never buy another 14.5" unless I go the SBR route.

I'll take the additional 1.5" of length, if it means I can remove my muzzle device with a simple wrench.

[Quentin]

I recently bought a Daniel Defense 16" LW midlength "build your own" upper and added MOE handguards. Really like this configuration/balance and can't see much penalty going with the extra inch+ and avoiding pinning. Of course apples to oranges because of MOE vs. long rail - and we all have different preferences.

Hope your new rifle turns out well!

[sdoperator]

I want the 14.5 simply because its shorter. I know its not much but i think the 14.5 balances a little better. Also, the optic that I will use is calibrated to a 14.5 inch barrel. Thanks for your input everyone i think i'm going to get the middy!
I've done the same, and love it. How many people weld on a muzzle device that they don't like? Not me. The one thing I will say is, get a two piece gas block unless you're sure your rails will never change.

Anyway, which optic are you going with?

[TehLlama]

I did a fantastic job of selecting my muzzle device by application - I have and LOVE my 14.5" M4SOC profiled barrel with SEI Vortex, my 14.7" CMMG LW carbine with pinned A2, and 14.5" LW Middy with BC1.5; but lacking the flexibility to change handguards and gas block/front sights is the limitation.

I'm still willing to go shortened/pinned on lightweight configurations that are low cost uppers, but outside of that, 16". That 1.5" is actually surprisingly hard to notice (select lighter components, you won't feel the difference), with a lighter (better usually) handguard, smaller weaponlight, lighter optic, and less junk, the balance is easier to fix.

[XCoastie]

I have a BCM 14.5 Middy with a Battle Comp 1.5 on it (pin and welded) and a Spikes buffer. I have to say its one of the softest shooting AR's I have ever used.

[ghostman1960]

I am absolutely enamored with my 14.5" middy.

http://i823.photobucket.com/albums/zz159/ghostman1961/DSCF2334-1.jpg

[Shrockp]

Im having a bit of trouble with A rifle I built for a friend, it is a 14.5 Middy barrel, with a VLTOR lo pro block, Stag receiver, PWS break. It also has a VLTOR A5 RE system, which we have tried in H0, H1, H2 buffers for the A5, and also a traditional buffer with both a H buffer, and carbine buffer. the problem is that it short strokes all the time, sometimes so that it only fails to lock open, and other times is only fires one round and short strokes enough to fail to feed a round. This has happened with everything we have tried, XM193, PMC 55 grain, LC m855, Federal American Eagle tactical .223 55, Hornady Tap training 75 gr, and both wolf and tula 55, it goes back and fourth between cycling enough to shoot through a mag, and then not loading the second round. Any ideas what to look at?

[Paulo_Santos]

Im having a bit of trouble with A rifle I built for a friend, it is a 14.5 Middy barrel, with a VLTOR lo pro block, Stag receiver, PWS break. It also has a VLTOR A5 RE system, which we have tried in H0, H1, H2 buffers for the A5, and also a traditional buffer with both a H buffer, and carbine buffer. the problem is that it short strokes all the time, sometimes so that it only fails to lock open, and other times is only fires one round and short strokes enough to fail to feed a round. This has happened with everything we have tried, XM193, PMC 55 grain, LC m855, Federal American Eagle tactical .223 55, Hornady Tap training 75 gr, and both wolf and tula 55, it goes back and fourth between cycling enough to shoot through a mag, and then not loading the second round. Any ideas what to look at?

Start from the front with the low profile gas block. Make sure that it installed properly and lined up properly. Then work your way up to the BCG. Is there anyway that you can check the size of the gas port on the barrel? I would also use the lightest buffer for now. Have you loaded just 1 round and see if the bolt stays locked back? You can also replace the BCG with a know good one, just to eliminate that out of the equation. And also use a different lower to make sure it isn't anything with the lower.

[AR-10]

I would check gas port alignment, and make sure you don't have a loose gas key.

What happens when you manually pull the charging handle, does the BCG come back far enough for the bolt catch to grab it?

I don't have any experience with the "A5" and am not even sure what kind of action spring it uses.

[markm]

I was fighting this issue with my 14.5 middy. Mine turned out to be an out of spec GAS TUBE, Boys! The tip that goes in the key should be .180" outer diameter. Mine was 0.010" below that with no step up to seal in the key.

Replaced it and it runs like a champ again. Your gas tube will tell you if there's excessive leakage by blackening too much forward of the key or behind the gas block.

[Stickman]

Mark- That is what you get for buying left over reject parts at the gun show....

On a more serious note, that is the first time I've heard of a gas tube being too thin.

[markm]

Mark- That is what you get for buying left over reject parts at the gun show....

On a more serious note, that is the first time I've heard of a gas tube being too thin.

I'm watching the new tube for any odd wear. I haven't figured out if the tube was never right, or if the key wore it down. Sometimes tubes will get a flat spot on one side or another. But this thing is smooth all the way around.

[Curlyburns5]

Sample size of one. But I have a BCM 14.5" lw middy I've put ~7500 rounds through. Of that, 90% has been cheap steel cased tulammo, bear, and wolf. As long as I keep the bolt wet I don't have a hiccup. With a battlecomp and an H buffer there's basically no recoil.

[FortTom]

I recently bought a Daniel Defense 16" LW midlength "build your own" upper and added MOE handguards. Really like this configuration/balance and can't see much penalty going with the extra inch+ and avoiding pinning. Of course apples to oranges because of MOE vs. long rail - and we all have different preferences.

Hope your new rifle turns out well!
I'm glad you brought this up. This debate comes and goes around with the "locals" here quite often. I just don't see any real advantage to a 14.5, then have to permanently afix your flash detector. My most recently acquired LMT is a 16 in., no worries about removing or changing flash suppresors. Also, and you can take this with a grain of salt, but at the time I read it, it seemed to make perfect sense, a pretty in depth look at the traditional gas system (DI) seems to work best with a 16 in barrel. I wish I would have saved the link, but wasn't thinking, but the author really seemed to have done his research, and the math to prove his assertion. So I can't prove any of that, but it was interesting. But I'm not sure if you're planning on a piston or a DI gas system, so all of that might be irrelevant anyway, if you're using a piston system.

Let us know how things work out for you.

FT

[Bob Reed]

Hello,

I would stay with the carbine length gas system for the simple reason of being able to use a high quality, Genuine COLT Gas Tube.

[Stickman]

I'm watching the new tube for any odd wear. I haven't figured out if the tube was never right, or if the key wore it down. Sometimes tubes will get a flat spot on one side or another. But this thing is smooth all the way around.


I've seen a bunch of gas tubes worn on one side, but you can usually see the gas tube is slightly off center.

[uniform 64]

So does a 16" Mid not have those short stroking issues?

[Stickman]

Hello,

I would stay with the carbine length gas system for the simple reason of being able to use a high quality, Genuine COLT Gas Tube.

Chunks coming off Colt receivers from poor anodizing, and unstaked Colt carriers are recent examples showing that no company is perfect, including Colt. It would appear they are cutting some of their QC for the commercial market.

[Stickman]

So does a 16" Mid not have those short stroking issues?

Yes, and no. There is more to it than simply barrel length. It is going to depend on the company and the gas port size they are using.

[Bob Reed]

Chunks coming off Colt receivers from poor anodizing, and unstaked Colt carriers are recent examples showing that no company is perfect, including Colt. It would appear they are cutting some of their QC for the commercial market.
Hello Stick,

That's sad to hear. Was it an entire run or just a few that had these problems?

I don't doubt you at all - but is there a thread or an article somewhere regarding this?

Other than buying older COLT A2 Style Rifles that come along - I've been buying Specialized Armament SA M4A1's, and the quality of SA's Weapons is simply outstanding!