Carbine or Mid-length Gas for 16" barrel?

Carbine system was a product of the Xm177 with a 10" bbl. The 14.5" carbine came later when they wanted to make a carbine using the xm177 gas tube and handguard, and to mount a bayonet 14.5" would be the right length.

16" carbine is simply a civilian offering to make use of standard carbine parts, to save money from developing and making new standard for the relative small commercial market back in the days. The reason we are stuck with some of the things we have pretty much boil down to the choices made 40 years ago at the development of xm177 and the mounting of M203, as well as the standard bayonet for m16. From that point on every variant needs to work around these items.

Interesting enough, the commercial mid length was first developed by Armalite ( probably with the engineering help of LMT?) so theoretically a bayonet can be mounted and it looks more "natural" to consumers as a product differentiation ( people always complained of the weird look of 16" carbine back then, hence the practice of wielding extended flash suppressor to 14.5). The advantage of the midlength was than applied backwards on the 14.5.
 
Hilo71 said:
Yeah it is good for Colt. The Carbine length gas system was designed to work. Shortest barrel possible, work everytime, for the soldier in the field. Mid lengths are the "abomination"
Yes, they do work, and the impulse is softer, it may run cooler and it may be easier on parts. BUT; with all the different ammo, buffers, gas port sizes etc in use with civvie mid lengths, there is no guarantee it will cycle ammo without a hiccup. Especially for someone buying an AR15 for the first time.

A good carbine gas system is usually overgassed. (larger port size)
Depending on your ammo (223, 5.56) you can 'tune" your carbine to make it shoot softer. Buffers, springs, muzzle device.....

I own both types of uppers. If you are not shooting suppressed full auto, a good Colt , DD, BCM, LMT type carbine gas system will last just as long as any mid length gas system weapon.
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I think you're missing the point. Carbine gas will work and no one is disputing that. However given the choice between mid and carbine the answer is mid. Yes a carbine will work but the over gassing issue is not a positive attribute. Mid more closely replicates rifle length which is what the AR fow was designed with from the get go.

A quality mid trumps any carbine. Increased dwell, reduced temp/pressure and softer recoil impulse all equate to a smoother more reliable and faster shooting rifle with increased life.

Tdc
 
TDC said:
I think you're missing the point. Carbine gas will work and no one is disputing that. However given the choice between mid and carbine the answer is mid. Yes a carbine will work but the over gassing issue is not a positive attribute. Mid more closely replicates rifle length which is what the AR fow was designed with from the get go.

A quality mid trumps any carbine. Increased dwell, reduced temp/pressure and softer recoil impulse all equate to a smoother more reliable and faster shooting rifle with increased life.

Tdc
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Not disputing your opinion. Just buying any midlength isn't a guarantee it's more reliable.
A midlength that works everytime with any ammo (insert BCM here) is over gassed. It has to be to cycle weaker ammo like Tula or PMC 223.
Shooting it side by side with a Colt carbine, one may not think it's softer shooting. Companies like BCM have opened up the gas port to cover most ammo types including cheap 223. (Since they sell A LOT of middies to hobbyists.)

A good middy with quality ammo, and an appropriate buffer weight will indeed tame the recoil, make it more comfortable to shoot and prolong parts. Most guys will not ever shoot enough to see that benefit though.
 
Hilo71 said:
Not disputing your opinion. Just buying any midlength isn't a guarantee it's more reliable.
A midlength that works everytime with any ammo (insert BCM here) is over gassed. It has to be to cycle weaker ammo like Tula or PMC 223.
Shooting it side by side with a Colt carbine, one may not think it's softer shooting. Companies like BCM have opened up the gas port to cover most ammo types including cheap 223. (Since they sell A LOT of middies to hobbyists.)

A good middy with quality ammo, and an appropriate buffer weight will indeed tame the recoil, make it more comfortable to shoot and prolong parts. Most guys will not ever shoot enough to see that benefit though.
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Just so everyone here is clear, when I or others in the know say that a mid is superior to a carbine gas system we are referring to quality offerings in both lengths, not cheap SH!t rifles so often purchased. Anything of poor quality will have issues hence the disclaimer regarding quality examples.

bcm gas ports on mid length guns are over gassed when compared to a rifle length system which is the standard. It also goes without saying that all carbine length guns are grossly over gassed. It is this issue that makes the mid superior over carbine. The mid is closer to the original/standard which is rifle length. The closer you get to the original the better it is overall.

Tdc
 
It seems as if my comment rustled some people on here. Also, just as a disclaimer I don't hate carbine length at all. Hence my 10.5 which I love dearly. However all the midlength rifles I've built this year have chewed everything and have ran flawlessly for their owners. And the difference is most definetly discernible to me when shooting them in terms of recoil. If you know how to set up a rifle properly it will eat anything as long as the ammo is good to go dimension wise. I build AR's that run reliably, and more importantly if I can, efficiently as possible. And midlength gas is the first step, if I have to build carbine gas length rifles(12.5 and under only!), then I usually like to pair them up with a vltor A5 buffer system.
 
Who produces the most AR types of guns? The US companies of course. The reason the 16 inch barrel and the midlength gas system has caught on is the laws here requiring at least a 16 inch barrel (without having to weld on your muzzle device) and not have to pay the NFA $200 tax. The logical solution was just to extend the gas system from a carbine length gas tube out to the FSB and get the benefits. The bastard systems are the ones that have a 16 inch barrel and sight radius of the middy but retain the carbine gas system. I personally chose the midlength system because of the shortest non-NFA barrel, choice of interchangeable muzzle devices, still mounts a bayonet, longer sight radius, longer handguard (carbine to short for me). If I have to have a non NFA barrel I might as well have the better gas system.
 
Is the mid length gas system 1.5 inches or 2.0 inches longer that carbine? If the latter, a 16.5 barrel would have the same bayo dimension as a 14.5 carbine.
 
Get a adjustable gas block for your stock setup, gives you control of your bolt speed. Its also a cheaper option to buying a new barrel and gas tube to whatever gas length you want to go.
 
I just bought a middy length barrel system because I like the looks. :)

Just considering aesthetic factor, I had to do it. I
I could not resist. I need the Kool Factor! :cool:

Okay, here is my carbine with a carbine gas system... Not a single hiccup ever! Super pleased!




No seriously, I already have a 12.5" barreled carbine for cqb fun and now I wanna try something different with a 14.5" heavy NEA barrel and Armalite stubby Picatinny gas block. You see I don't need any rails or lights or PAQ 14 to make JTF3 tryouts. I'm
already too ugly to deploy so ORA CQB matches work for me! Yuk yuk yuk :)

Back in 2006 Service Rifle days I ran with a RRA 16" barreled middy system and was very happy. Now I'm heading back tohome e middy system to regains once LCF; looks cool factor. Ha ha ha ha

Here is my middy:



Whatever size you purchase, build, inherit, trade for, and acquire, get out and shoot your boomstick at your local competition! Have fun, network, build community! :evil:


Cheers and keep helping them noobies out there! :wave:

Barney
 
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TacticalTeacher said:
I just bought a middy length barrel system because I like the looks. :)

Just considering aesthetic factor, I had to do it. I
I could not resist. I need the Kool Factor! :cool:

Okay, here is my carbine with a carbine gas system... Not a single hiccup ever! Super pleased!




No seriously, I already have a 12.5" barreled carbine for cqb fun and now I wanna try something different with a 14.5" heavy NEA barrel and Armalite stubby Picatinny gas block. You see I don't need any rails or lights or PAQ 14 to make JTF3 tryouts. I'm
already too ugly to deploy so ORA CQB matches work for me! Yuk yuk yuk :)

Here is my middy:



Whatever size you purchase, build, inherit, trade for, and acquire, get out and shoot your boomstick at your local competition! Have fun, network, build community! :evil:

Cheers and keep helping them noobies out there! :wave:
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Hey Barney, I think the CGN community is very lucky to have you. You are one of the few people I've ever met that is always looking for ways to give more than they receive. :cheers:
 
Working on a AR for Service rifle... Yes, Yes, it has been an ongoing saga for at least 5 yrs but the gun is built and shooting.

mid length gas on this 18" McGowen. WOW, is it every soft shooting. I love it

With the tweaks I did to help soften the original Norc set up and carbine system, the rifle was alot better then original but nothing like this.

AND the accuracy seems to be really really good. Only 1 range trip for testing but groups were the smallest I have ever shot with an AR.

Neat.

Jerry

PS,does thing improve anymore when going from mid to rifle length?
 
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Funny, but 14.5" barrel with carbine gas system and 16" barrel with mid length gas system are pretty much going head to head in terms of performance. Flavour of the month...we are discussing here. It really doesn't matter. Pick up the one that works best for you.
 
I have a 10.5" Noveske with a carbine length gas system.
A 14.5" Noveske with a mid length gas system.
An 18" Stag with a rifle length gas system.

They shoot much smoother than a 14.5" with carbine gas, 16"-18" with mid length gas.
I would also go intermediate gas on a 16" barrel.
 
Jerry

Many years ago the were some very early models of the Bushmaster Dissipater carbine floating around, I don't know how many, or if any made it up here to Canada. They had what in reality was a cut down rifle barrel with rifle length gas system. This was well before the C-68 fiasco...

Anyway, they worked just fine, and the gas port hole was the same or very slightly larger than the std rifle size. There was not much "Cool factor" to them and for that reason they didn't catch on, but they worked!

Chuck Taylor tried some of these and wrote an article on it.



QUOTE=Mystic Precision;10910611]Working on a AR for Service rifle... Yes, Yes, it has been an ongoing saga for at least 5 yrs but the gun is built and shooting.

mid length gas on this 18" McGowen. WOW, is it every soft shooting. I love it

With the tweaks I did to help soften the original Norc set up and carbine system, the rifle was alot better then original but nothing like this.

AND the accuracy seems to be really really good. Only 1 range trip for testing but groups were the smallest I have ever shot with an AR.

Neat.

Jerry

PS,does thing improve anymore when going from mid to rifle length?[/QUOTE]
 
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Dissipator was a carbine length gas system 16 inch bbl under regular length handguards and a dummy front gas block/sight.
 
robin2y said:
Dissipator was a carbine length gas system 16 inch bbl under regular length handguards and a dummy front gas block/sight.
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The new ones were, however some of the older ones (and you can actually still find some newly manufactured ones today) that were a 16" barrel with rifle length gas system. They never really worked properly, and IIRC had to have a much larger gas port to compensate for the lower pressure and very low dwell time.

I definitely like the midlength gas system, everything runs at a lower pressure and part last longer as they're not unlocking as aggressively. And you also get a longer handguard if you want to use standard plastic handguards to keep weight down (not an issue at all if you go with a free float rail system).
 
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