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

Assegai 18-inch Mid-Gas 1:24 .450 Bushmaster AR-15 M-LOK Handguard Rifle Full Build Kit

The Assegai is a complete .450 Bushmaster build kit built around a heavy barrel profile and mid-length gas system designed for controlled recoil and reliable cycling in this large-bore caliber. This kit includes everything except the lower receiver: an 18-inch 4150 CrMoV barrel with 1:24 twist rate, free-float M-LOK handguard, mil-spec bolt carrier group, charging handle, lower parts kit, buffer system, and SOPMOD-style stock with integrated storage.

Key Features

• 18-inch HBAR 4150 CrMoV barrel with 1:24 twist rate for .450 Bushmaster
• Free-float 15-inch M-LOK handguard with no forward assist upper receiver
• Mid-length gas system with stainless steel tube and micro low-profile gas block
• .458 SOCOM/.450 Bushmaster bolt carrier group with enlarged ejection port
• Complete mil-spec lower parts kit, 6-position carbine buffer tube, and SOPMOD stock
• KAK Industry .458 compensator with 5/8x32 thread pitch included
• Heavy-duty 3 oz. standard carbine buffer and USA-made recoil spring

Perfect For

• Shooters building a large-bore AR-15 platform for hunting or long-range shooting
• Builders who want a complete kit with all upper and lower components ready to assemble
• Those seeking a heavy-hitting .450 Bushmaster rifle without sourcing individual parts

Free-Float Handguard Design

The 15-inch free-float M-LOK handguard isolates the barrel from pressure and vibration, improving accuracy potential by allowing the barrel to return to the same position with each shot. M-LOK mounting slots provide a modular accessory ecosystem for lights, grips, and other attachments without adding weight or complexity. Black finish matches the receiver and stock for a cohesive appearance.

Mid-Length Gas System and Recoil Management

Mid-length gas tube positioning balances dwell time and recoil impulse in the .450 Bushmaster caliber. The micro low-profile gas block maintains a clean profile under the handguard while the stainless steel tube resists corrosion. The 3 oz. standard carbine buffer paired with the USA-made recoil spring handles the heavier recoil of .450 Bushmaster ammunition while keeping the rifle controllable.

Billet Upper and Enlarged Ejection Port

The Panhead billet upper receiver features an enlarged .458-style ejection port designed specifically for .450 Bushmaster brass, which is significantly larger than standard 5.56 cases. The no forward assist configuration reduces weight and maintains a clean upper receiver profile. AR-15 ejection port door with rod and spring keeps debris out of the action.

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