Use for a new modern sporting rifle build, or convert any existing AR-15 to .450 Bushmaster with this complete upper assembly from Great Lakes Firearms and Ammunition. It features an 18" heavy match grade barrel made from chrome moly alloy steel. The A3 style upper is made from aircraft grade aluminum and has an oversized ejection port. The upper comes complete with a free float handguard, low profile gas block, mid length gas system and phosphate coated bolt carrier group.

Specifications and Features
Great Lakes Firearms and Ammunition UR450BUSH
.450 Bushmaster
Aircraft aluminum A3 upper
M4 feed ramps
18" chome moly heavy match grade barrel
1:24" twist
11/16-24 muzzle threads
Mid length gas system
Low profile gas block
Free float handguard
Oversized ejection port
Phosphate coated bolt carrier group
Fits all standard AR-15 lower receivers
Black