Details
Buffalo Bill 18-inch Mid-Gas 1:24 .450 Bushmaster AR-15 Freefloat M-LOK Upper Build Kit
The Buffalo Bill is a .450 Bushmaster AR-15 Upper Build Kit built around an 18-inch mid-length gas platform. The kit centers on an 18-inch HBAR profile barrel in 4150 CMV steel with a phosphate finish, 1:24 twist rate, and 5/8x32 thread pitch, paired with a KAK .458 compensator and a black crush washer. A micro low-profile steel 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 billet AR-15 design with an enlarged .458 ejection port, an ejection port door assembly, and a forward assist compatible configuration, paired with a 15-inch freefloat M-LOK handguard featuring an ultra-lightweight minimalist profile, a partial-length Picatinny top rail, M-LOK accessory mounting slots, and no anti-rotation tabs. BCG and charging handle are not included.
Key Features
- 18-inch HBAR profile barrel, 4150 CMV 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 steel gas block, 0.750
- KAK .458 compensator, 5/8x32, black crush washer included
- Billet AR-15 upper receiver, enlarged .458 ejection port, ejection port door assembly, forward assist compatible
- 15-inch freefloat M-LOK handguard, ultra-lightweight minimalist profile, partial-length Picatinny top rail, M-LOK accessory mounting slots, no anti-rotation tabs
- BCG and charging handle not included
Perfect For
- Builders sourcing a complete .450 Bushmaster AR-15 upper build kit with a billet upper receiver featuring an enlarged .458 ejection port, KAK .458 compensator, and 15-inch freefloat M-LOK handguard, pairing it with their own bolt carrier group and charging handle
- Shooters building an 18-inch .450 Bushmaster mid-gas platform who prefer to select their own BCG while having the HBAR barrel, mid-length gas system, and lightweight freefloat M-LOK handguard covered in one kit
- AR-15 builders who want a .450 Bushmaster upper build kit with a billet upper receiver and KAK .458 compensator at a 5/8x32 thread pitch without sourcing components separately
Barrel and Muzzle Device
The 18-inch HBAR profile barrel is chambered in .450 Bushmaster and constructed from 4150 CMV 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 crush washer, a micro low-profile steel 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.
Billet Upper Receiver and Handguard
The billet AR-15 upper receiver features an enlarged .458 ejection port sized for the .450 Bushmaster cartridge, an ejection port door assembly, and a forward assist compatible configuration. The 15-inch freefloat M-LOK handguard features an ultra-lightweight minimalist profile, a partial-length Picatinny top rail, and M-LOK accessory mounting slots along the body. No anti-rotation tabs are present on this handguard. 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.
