Davidson Defense Buffalo Bill 18-inch Mid-Gas 1:24 .450 Bushmaster AR-15 Freefloat M-Lok Handguard Rifle Full Build Kit

Buffalo Bill 18-inch Mid-Gas 1:24 .450 Bushmaster AR-15 Freefloat M-LOK Rifle Full Build Kit

The Buffalo Bill is a .450 Bushmaster AR-15 Full Build Kit built around an 18-inch mid-length gas platform. The kit centers on an 18-inch HBAR profile barrel in 4150 CrMoV steel with a phosphate finish, 1:24 twist rate, and 5/8x32 thread pitch, paired with a KAK .458 compensator at 5/8x32 and a black 5/8-inch crush washer. A micro low-profile gas block at 0.750 diameter and a mid-length stainless steel gas tube are included on the front end. The upper receiver is a Panhead billet 6061-T6 aluminum design with an anodized finish, an enlarged .458 ejection port door with rod and spring, and no forward assist, paired with a 15-inch freefloat M-LOK handguard in 6061-T6 aluminum. A complete .458 SOCOM and .450 Bushmaster compatible bolt carrier group in 9310 alloy steel with a phosphate finish and a Mil-Spec AR-15 M4 charging handle complete the upper side. The lower hardware includes a complete Mil-Spec AR-15 lower parts kit, a Mil-Spec heavy-duty 6-position buffer tube, a standard 3 oz carbine buffer, a USA-made standard AR-15 carbine recoil spring, an AR-15 M16 Mil-Spec receiver end plate, and an AR-15 carbine castle nut. The Adaptive Tactical EX Performance adjustable stock rounds out the kit. Lower receiver not included.

Key Features

• 18-inch HBAR profile barrel, 4150 CrMoV steel, phosphate finish, 1:24 twist, 5/8x32 thread pitch, .450 Bushmaster
• Mid-length gas system
• Mid-length stainless steel gas tube
• Micro low-profile gas block, 0.750
• KAK .458 compensator, 5/8x32, black 5/8-inch crush washer included
• Panhead billet 6061-T6 aluminum upper receiver, anodized, enlarged .458 ejection port door with rod and spring, no forward assist
• 15-inch freefloat M-LOK handguard, 6061-T6 aluminum
• Complete .458 SOCOM and .450 Bushmaster bolt carrier group, 9310 alloy steel, phosphate finish
• Mil-Spec AR-15 M4 charging handle
• Complete Mil-Spec AR-15 lower parts kit
• Mil-Spec heavy-duty 6-position buffer tube
• Standard carbine buffer, 3 oz
• Standard AR-15 carbine recoil spring, made in USA
• AR-15 M16 Mil-Spec receiver end plate
• AR-15 carbine castle nut
• Adaptive Tactical EX Performance adjustable stock

Perfect For

• Builders sourcing a complete .450 Bushmaster AR-15 full build kit with a Panhead billet upper receiver, KAK .458 compensator, .450 Bushmaster compatible BCG, and Adaptive Tactical EX Performance stock already included, pairing it with their own lower receiver
• Shooters building an 18-inch .450 Bushmaster mid-gas rifle platform who want the BCG, charging handle, buffer system, and adjustable stock covered in one kit with a KAK .458 compensator at 5/8x32
• AR-15 builders who want a .450 Bushmaster full build kit with a Panhead billet upper receiver featuring an enlarged .458 ejection port and a 9310 alloy steel phosphate BCG without sourcing components separately

Barrel and Muzzle Device

The 18-inch HBAR profile barrel is chambered in .450 Bushmaster and constructed from 4150 CrMoV steel with a phosphate finish. The twist rate is 1:24 and the thread pitch is 5/8x32, which matches the included KAK .458 compensator. A black 5/8-inch crush washer, a micro low-profile gas block at 0.750 diameter, and a mid-length stainless steel gas tube cover the front end gas configuration on this mid-length platform.

Panhead Billet Upper Receiver and Handguard

The Panhead billet 6061-T6 aluminum upper receiver carries an anodized finish with an enlarged .458 ejection port door, rod, and spring for the .450 Bushmaster cartridge. No forward assist is present on this receiver. The 15-inch freefloat M-LOK handguard is 6061-T6 aluminum with 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.

Bolt Carrier Group and Charging Handle

The complete bolt carrier group is 9310 alloy steel with a phosphate finish and is compatible with .458 SOCOM and .450 Bushmaster. A Mil-Spec AR-15 M4 charging handle is included to complete the upper component set.

Lower Parts Kit and Buffer System

The complete Mil-Spec AR-15 lower parts kit covers the internal lower receiver components. The buffer system includes a Mil-Spec heavy-duty 6-position buffer tube, a standard 3 oz carbine buffer, a USA-made standard AR-15 carbine recoil spring, an AR-15 M16 Mil-Spec receiver end plate, and an AR-15 carbine castle nut. The Adaptive Tactical EX Performance adjustable stock pairs with the included Mil-Spec buffer tube and covers the rear stock interface for this build.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. Lower receiver not included.