The Noveske 16 Inch Stainless Steel, medium weight Recon 5.56mm barrel group consists of a 1 in 7 twist improved polygonal rifled barrel, 5.56 Noveske Match Mod 0 chamber with a mid length gas system. Extended M4 feed ramps with 1/2x28 TPI muzzle threads. Bead blasted finish, 1" long gas block seat, pinned low profile gas block. 

Comes complete with lo-pro gas block, gas block pin, gas tube and gas tube roll pin.

The 7.5" Stainless Steel, medium weight Diplomat 5.56mm barrel group consists of a 1 in 7 twist improved polygonal rifled barrel. 5.56 Noveske Match Mod 0 chamber with a pistol gas system. Extended M4 feed ramps with 1/2x28 TPI muzzle threads. Bead blasted finish, 1" long gas block seat, pinned low profile gas block.

Comes complete with lo-pro gas block, gas block pin, gas tube and gas tube roll pin.

Daniel Defense 16 inch Cold Hammer Forged, govt. profile barrel.  Machined from ordnance-grade 4150 Chrome Moly Vanadium alloy steel for exceptional strength, and magnetic particle inspected (MPI) to ensure there are no internal flaws in the metal.  Chrome lined 5.56 NATO bore and chamber, M4 ramped barrel extension with 1/7 twist rate, .750 diameter gas block journal, midlength length gas system, and 1/2-28 threaded muzzle.

Rock River Arms 20 Inch air-gauged, cryo-treated, stainless steel, varmint barrel chambered in .223 Wylde with a 1:8 twist, rifle-length gas system, and a non-threaded, target crown muzzle.  The Barrel Diameter is .920 in front of the gas block and 1.050 behind.  Also included is RRA's Single rail gas block with gas tube roll pin.