| '''Rifle''' || 20 inches || Weight +1 tier<br/>Muzzle: Standard devices<br/>Bayonet compatibility: [[M9 bayonet]] || [[Colt AR-15A2 R6550]]<br/>[[Colt M16A1]]<br/>[[Colt M16A2]]<br/>[[Colt M16A4]] || '''600''' || Installs a 20 inch barrel, as originally intended for the platform.
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| '''Carbine''' || 14.5 inches || Muzzle: Standard devices<br/>Bayonet compatibility: [[M9 bayonet]] || [[Colt M4A1]] || '''300''' || Installs an M4 style 14.5 inch barrel, which provides a compromise between performance and weight. Considered to be the modern standard length for AR-15 riflesplatforms.
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| '''Competition''' || 12.5 inches || Weapon becomes Class 2<br/>Muzzle: Standard devices || || '''600''' || Installs a short 12.5 inch barrel designed for competition shooting such as 3-gun.