AR15 Barrels

Major Options – Length, twist, caliber, chrome lined, profile, chamber, material, quality/testing, gas tube, Front Sight, Gas block
Rifling twist options – 1:7, 1:9, 1:12
Costs $200-$600
Tier One – High Pressure Testing (HPT), Magnetic Particle Inspection (MPI)
Tier Two – Chrome Lining – not true 5.56 chambers
Other Parts Required: Gas tube, gas block, front sight assembly, Delta ring assembly, handguards / rail assembly, muzzle device, bayonet lug


Things to consider about AR-15 Barrels

Barrel Length

Standard length for the AR15 barrel are; 7″, 10″, 10.5″, 11.5″, 14.5″, 16″, 18″, 20″ and 24″. Most common are 16″ and 20″. NFA rules apply to Short Barreled Rifles (SBR), rifles with a barrel under 16″ long. However many people buy the 14.5″ barrel and permanently attach a 2″ flash hider to maker the overall length over 16″ and legal without an NFA tax stamp

AR15 Barrel Profile

  • ‘Hollywood’ : ArmaLite Early AR-15 ultra-lightweight turned-down profile barrel, 1:14 twist
  • A1: Government-specified barrel profile increased to between 0.675 and 0.575 inches “lightweight” or “pencil” profile.
  • A2: Thin barrel under handguards, barrel in front of handguards is thickened to 0.715 inches. “Government Profile” or “gov’t profile”
  • HBAR: A barrel that is thicker than government-profile
  • M4 (14.5″ or 16″): section reduced to 0.575 inches to mount M203 grenade launcher
  • M4A1 HBAR: 14.5″ M4 barrel thickened under handguard for automatic fire
  • Super Heavy: Special target / match barrel

AR15 Gas System Length

Three common and a shorter pistol length. Standard gas system lengths are; carbine, mid length, rifle

AR15 Barrel twist

  • 1:14  1 right hand twist every 14 inches
  • 1:12  1 right hand twist every 12 inches (305 mm)
  • 1:10  1 right hand twist every 10 inches
  • 1:9    1 right hand twist every 9 inches
  • 1:7    1 right hand twist every 7 inches (177.8 mm)

More on the way

  • Chrome lined chamber and bore
  • AR15 Fluted Barrel
  • headspacing
  • Cold Hammer Forged barrels
  • Stainless Steel
  • Government Profile
  • HBAR
  • Barrel marking
  • barrel nut

AR-15 Barrel Parts List

  • Barrel
  • Barrel extension
  • delta ring
  • barrel nut
  • Gas tube (carbine, mid, rifle)
  • Weld Spring
  • Gas tube pin
  • Snap Ring

Changing the barrel on an AR-15

AR15 Barrel Length & Profile Comparison

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