The M-15A4 carbine complete upper assembly features a double lapped, chrome lined\chrome moly vanadium barrel. The MIL-STD 1913 rail on the upper receiver and the gas block allow rapid and repeatable interchange of removable iron or scope sights.
Each Armalite complete upper assembly includes a forged upper receiver assembly, barrel assembly, bolt carrier group and charging handle assembly. All complete upper assemblies are test fired as complete rifles before shipping.
.750 at the journal (under the gas block)
Model: M-15 carbine complete upper half assembly
Caliber: 5.56X45 mm / .223
Barrel: 16" double lapped, chrome lined\chrome moly vanadium MIL-B-11595-E, M-4 feed ramps
Rifling Twist: 1:7" RH
Muzzle Device: Flash suppressor, threading:1/2" - 28
Front Sight Base: Gas block with MIL-STD 1913 rail top of gas block is .293 (+/-) lower than top of upper receiver
Upper Receiver: Forged flat-top with MIL-STD 1913 rail, 7075-T6 aluminum
Finish: Hard anodized aluminum, manganese phosphated steel