Davidson Defense Boar Spear 18-inch Mid-Length-Gas 1:24 .450 Bushmaster AR-15 Freefloat M-Lok Handguard Rifle Upper Build Kit

Boar Spear 18-inch Mid-Length-Gas 1:24 .450 Bushmaster AR-15 Freefloat M-LOK Rifle Upper Build Kit

The Boar Spear 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 4150 CrMoV steel barrel with a phosphate finish, 1:24 right-hand twist rate, and 5/8x32 thread pitch, paired with a KAK .458 compensator and a black 5/8-inch 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 Panhead billet upper receiver features an enlarged .458 ejection port door, paired with a 15-inch ACE Series freefloat M-LOK handguard. BCG and charging handle are not included.

Key Features

• 18-inch HBAR profile 4150 CrMoV steel barrel, phosphate finish, 1:24 right-hand 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 5/8-inch crush washer included
• Panhead billet upper receiver, enlarged .458 ejection port door
• 15-inch ACE Series freefloat M-LOK handguard
• BCG and charging handle not included

Perfect For

• Builders sourcing a .450 Bushmaster AR-15 upper build kit with an 18-inch HBAR phosphate 4150 CrMoV barrel, Panhead billet upper receiver with enlarged .458 ejection port, KAK .458 compensator, and 15-inch ACE Series freefloat M-LOK handguard, pairing it with their own .450 Bushmaster bolt carrier group and charging handle
• Shooters building an 18-inch mid-gas .450 Bushmaster rifle platform who prefer to select their own BCG while having the HBAR phosphate 4150 CrMoV barrel, Panhead billet upper receiver with enlarged .458 ejection port door, and ACE Series freefloat M-LOK handguard covered in one kit
• AR-15 builders who want a .450 Bushmaster upper build kit with a KAK .458 compensator at 5/8x32 and a 15-inch ACE Series freefloat M-LOK handguard 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 right-hand 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 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.

Upper Receiver and Handguard

The Panhead billet upper receiver features an enlarged .458 ejection port door sized for the .450 Bushmaster cartridge. The 15-inch ACE Series freefloat M-LOK handguard features M-LOK attachment points along the body for accessory mounting. These two components define the exterior structure of the upper assembly on this AR-15 platform.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. BCG and charging handle are not included. Verify compatibility with your specific .450 Bushmaster lower receiver and bolt carrier group before use.