The Bushmaster XM-15 16" Heavy Barrel Carbine provides heavy-duty performance whenever duty calls. The heavy profile 16" chrome moly vanadium steel barrel is manganese phosphate-finished to insure protection against corrosion and rust, and the carbine features a threaded birdcage flash suppressor and a 6-position telescoping stock. The upper and lower receivers are machined from 7075-T6 aircraft aluminum forgings for light weight and added strength, and the upper receiver is offered in A2 or A3 configurations. The A2 upper receiver (SSI 13233) features a fixed carry handle and has a 300-800 meter rear sight system with 1 MOA elevation and 1/2 MOA windage adjustments. The carbine ships with a 30-round magazine.