Davidson Defense Col Cooper 10.5-inch Carbine-Gas 1:24 .450 Bushmaster AR-15 M-Lok Handguard Pistol Upper Build Kit

Davidson Defense Col Cooper 10.5-inch .450 Bushmaster AR-15 Freefloat M-LOK Pistol Upper Build Kit

The Davidson Defense Col Cooper is a .450 Bushmaster AR-15 Upper Build Kit built around a compact 10.5-inch carbine-length gas platform. The kit centers on a 10.5-inch H-Bar barrel in steel with a 1:24 twist rate and 5/8x32 thread pitch, paired with a KAK .458 compensator and a black crush washer. A low-profile gas block at 0.750 diameter and a stainless steel gas tube are included on the front end. The Panhead billet upper receiver features an enlarged .458 ejection port door, paired with a 10-inch ultra-lightweight minimalist freefloat M-LOK handguard with a partial top rail and no anti-rotation tabs. BCG and charging handle are not included.

Key Features

• 10.5-inch H-Bar barrel, steel, 1:24 twist, 5/8x32 thread pitch
• Carbine-length gas system
• Stainless steel gas tube
• Low-profile gas block, 0.750
• KAK .458 compensator, 5/8x32, black crush washer included
• Panhead billet upper receiver, enlarged .458 ejection port door
• 10-inch ultra-lightweight minimalist freefloat M-LOK handguard, partial top rail, no anti-rotation tabs
• BCG and charging handle not included

Perfect For

• Builders sourcing a compact .450 Bushmaster AR-15 upper build kit and pairing it with their own bolt carrier group and charging handle
• Shooters building a 10.5-inch .450 Bushmaster pistol platform who already have a lower receiver and prefer to select their own BCG
• AR-15 builders who want a Panhead billet upper with an enlarged .458 ejection port and KAK compensator covered in one upper kit

Barrel and Muzzle Device

The 10.5-inch H-Bar barrel is chambered in .450 Bushmaster and constructed from steel with a 1:24 twist rate. The thread pitch is 5/8x32, which matches the included KAK .458 compensator. A black crush washer, a low-profile gas block at 0.750 diameter, and a stainless steel gas tube cover the front end gas configuration on this carbine-length platform.

Panhead Upper Receiver and Handguard

The Panhead billet upper receiver features an enlarged .458 ejection port door to accommodate the .450 Bushmaster cartridge. The 10-inch ultra-lightweight minimalist freefloat M-LOK handguard features a partial top rail and no anti-rotation tabs, providing M-LOK attachment points along the body for accessory mounting. These two components define the exterior structure of the upper assembly on this .450 Bushmaster platform.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. BCG and charging handle are not included.