10.5 vs 11.5

[The-S]

Its about that time to build a shorty ar-15 for myself and I am torn between the two barrels. Does anyone know the difference in ballistics and advantages/disadvantages for both.

Thanks in advance.

[Stickman]

For a long time the 11.5 was considered a more reliable barrel length, plus it had the additional velocity for fragmentaion. The main reason the 10.5 stuck around was because of the military using it. Now, things have changed a bit, and the 10.5s are pretty squared away.



Paul from BCM has mentioned in the past that the 11.5, with its extra inch of barrel past the gasport, retains a 40% longer dwell time than the 10.5". I think you start to really see this become important as weapons get dirty, temperatures change, weaker ammo is used, or other things come into play.

[The-S]

Thanks stick. On paper the 11.5 seems to be the better choice correct?
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[Stickman]

Yes, unless you are looking for a Military clone.

[rob_s]

Depends on use too as well as suppressor choice. Some people still want the smallest overall package they can get and they accept the shorter service life and effective range of the shorter barrel.

[The-S]

shorter life? I also will not be running a suppressor.
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[TehLlama]

If you're not running a can, 11.5" for sure, even consider a 12.5".

Mine is going to be suppressed all the time (gas port tweaks as well), so the 10.5" made sense, but it's hard not to appreciate the better looking muzzle velocity from the longer barrels.

[Stickman]

shorter life? I also will not be running a suppressor.

Yes, the 10.5" is more violent, so it ends up being higher wear and tear. The 10.5" barrels are brutal on cans.

[The-S]

good to know. 11.5 it is :) Stick you wouldnt happen to have a picture of a 12in rail with an 11.5in barrel and a kx3 would ya?
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[Stickman]

good to know. 11.5 it is :) Stick you wouldnt happen to have a picture of a 12in rail with an 11.5in barrel and a kx3 would ya?

[The-S]

looks exactly like my gun now just shorter :) EXCITED! Going to file my paperwork tomorrow!

[Stickman]

Just remember, the Daniel Defense M4 series rails will accept the KX3, the LITE Rails will not.

[The-S]

Yes sir. The only rifle length rail I own at the moment is a YHM but that will soon change. I still haven't made up my mind if I want to use the kx3 or the troy claymore I have.
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[markm]

The 10.5 is pretty useless to me. I'd never put a can on something that short unless my goal was to destroy it as quickly as possible. I don't even run my can on my 11.5s or anything shorter than 14.5. As far as the KX3. That thing is complete nonsense.
I'd take the equivalent additional REAL barrel length over that boat anchor and actually get some gain in velocity.

[TehLlama]

I guess I forgot to mention that for the most part I'd be abusing a $200 can with mine, so mercilessly annihilating it's single baffle (OPS M4S) isn't such a concern for me. I'll try to find the pictures of the coning on muzzle brakes and baffles from the 10.5" and 12.5" barrels.