How does a short barrel AR-15 compare to a 16" barrel?


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bushmaster1313
August 15, 2011, 11:28 PM
Compared to a 16" AR-15, other than making it an NFA, what is the effect of shortening the barrel to 12 or 14 inches?

Muzzle blast
accuracy
Range
Muzzle energy
Follow-up shots

Thank you

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Zak Smith
August 16, 2011, 02:05 AM
Lose a couple hundred FPS.

Mechanical accuracy should not be affected provided the barrel is good and the upper is built right.

Effective range is decreased as a function of terminal velocity. External ballistics are reduced with reduced muzzle velocity.

Muzzle blast is increased.

It is typically a little harder to make a shorter barrel run as reliably as a 14.5"+, but it can be done. I have a 12" that runs flawlessly.

Dustin0
August 16, 2011, 09:02 AM
I am currently fighting a 7.5 SBR. To get the gun to run correctly you will need a heavy buffer M16 Bolt Carrier and a fender D extractor. I hoping that will sovle my problems.

Follow up shots and accuracy have not been a problem with the break I used. It also cut down on the muzzle blast alot.

rjrivero
August 17, 2011, 11:31 AM
My 7.5" is harsh on the ears, if you're using any kind of muzzle brake. So much so that I built an 11" upper for it. It's much more plesant to shoot.

jbg762
August 19, 2011, 02:11 PM
Has anyone on here actually run any rounds from a 7 or 11 inch .223 through a chrono? I've been looking for a solid answer to this very question for months. I have an Eagle Arms EA-15 I want to register as an SBR and I'm trying to decide on barrel length. I'm kind of leaning towards a lightweight A1 profile 11.5 inch barrel. I don't think I want to have to deal with the pistol length handguards and I've heard the 11.5 is more reliable than the 10.5 without any tweaking. I've read a lot of posts by armchair commandoes who quote the 50 fps per inch "rule". Of course I imagine in the real world you lose a lot more than that once you start getting much below about 14 inches.

Zak Smith
August 19, 2011, 04:09 PM
12.5"
Mk262 - 2500
M855 - 2750
M193 - 2850

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