There is much confusion about the effects of these short barrels on velocity. It makes sense that a shorter barrel will produce lower velocity, but how much less? Since the Army rolled out the 14.5 inch barrelled M-4 in 1992, there have been a lot of people shooting shorter barrels. The SEALs developed the Mk18 with a 10.3 inch barrel and many military and law enforcement units have gone short. AR pistols have brought shorter barrels to the common man.
Over the last year or so, Eagle_19er posting on AR15.com has gathered forty-one different factory loads and tested 10 rounds of each in a 10.5″, 11.5″, 12.5″ and 14.5″ barreles to establish a baseline velocities. They run the gamut from 55gr Wolf Polyformance steel case to a few flavors of heavy OTM loads.
It’s by no means an exhaustive list of everything available in 5.56, but these loads cover many of the popular “off the shelf” (and a few more obscure) loads that many of us shoot at the range and/or depend on for self defense, hunting or duty.
You can see all of Eagle_19er’s work on AR15.com: Suppressed 5.56 SBR Velocity Tests–41 Factory Loads from 10.5″, 11.5″, 12.5″ & 14.5″ ALL DONE
Guns used:
- 10.5″ Noveske SwitchBlock with SilencerCo Omega suppressor
- 11.5″ Faxon “Big Gunner” (Mid Gas) with SilencerCo Omega suppressor.
- 12.5″ BCM Standard (Carbine gas) with SilencerCo Omega suppressor.
- 14.5″ BCH BFH “Barrel – Hammer Forged” (Mid Gas) with SilencerCo Omega suppressor.
Ammo:
- Speed Gold Dot 55 Grain Bonded
- Speer Gold Dot 64 Grain Bonded
- Speed God Dot 75 Grain Bonded
- Barnes 55 Grain TSX-FB
- Barnes 62 Grain TSX-BT
- Barnes 70 Grain TSX-BT
- Federal Fusion MSR 62 Grain Bonded
- Black Hills 77 Grain Sierra TMK
- Black Hills 77 Grain OTM
- Australian Outback 55 Grain Blitzking
- Australian Outback 69 Grain Matchking
- Federal 69 Grain Matchking
- Remington 55 Grain PSP
- Fiocchi 55 Grain Soft Point
- PPU 75 Grain HBPT Match
- Hornady Black 75 Grain BTHP
- IMI 77 Grain OEM LR Mod 1
- IMI M193
- PPU M193
- PMG XTAC XP193
- Winchester 5.56 55 Grain FMJ (Q3131)
- Federal XM193
- Federal .223 FMJ 55 Grain (AE223J)
- PMC Bronze 55 Grain
- Wolf Gold 55 Grain
- MEN M193
- Norma Tac 223 55 Grain
- Wolf Polyformance 55 Grain (Steel Cased)
- Hornady Steel (Steel Cased)
- Silver Bear 62 Grain SP (Steel Cased)
- Tula 75 Grain HP (Steel Cased)
With this kind of data, you can make an educated decision about which barrel length is right for you.