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″ barrels 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.

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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)

Complete tables show the velocity, extreme spread, SD, and the actual shot string data for each barrel length.

With this kind of data, you can make an educated decision about which barrel length is right for you.

 

This article is courtesy of Mark Miller from The Loadout Room.