450 Bushmaster AR-15 Upper Assemblies

.450 Bushmaster

Shop .450 Bushmaster AR-15 uppers from Moriarti in multiple barrel lengths, handguard styles and finishes. Built around the AR-15 platform, .450 Bushmaster offers a large-bore configuration popular with hunters and shooters looking for a straight-wall cartridge option. Browse compact and rifle-length .450 Bushmaster upper assemblies and compare barrel length, twist rate, muzzle device, rail and included components to find the right configuration for your AR-15 lower.

What parts are different when using a .450 Bushmaster upper on an AR-15 lower?

A .450 Bushmaster upper uses caliber-specific components such as the barrel and compatible bolt, and the firearm requires magazines designed or configured for reliable .450 Bushmaster feeding. The lower remains based on the AR-15 platform, but buyers should verify the individual upper's bolt, magazine and buffer-system requirements before selecting supporting components.