Davidson Defense Lochness 18-inch Mid-Gas 1:24 .450 Bushmaster AR-15 Freefloat Keymod Handguard Rifle Upper Build Kit

Lochness 18-inch Mid-Gas 1:24 .450 Bushmaster AR-15 Freefloat Keymod Upper Build Kit

The Lochness 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 compatible with .458 and .450 Bushmaster, 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 Panhead billet aluminum design with an enlarged .458 pattern ejection port and an ejection port door with rod and spring, paired with a 15-inch Trinity Force ECHO freefloat Keymod handguard with a full-length Picatinny top rail. 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, .458 and .450 Bushmaster compatible, black crush washer included
• Panhead billet aluminum upper receiver, enlarged .458 pattern ejection port, ejection port door with rod and spring
• Trinity Force ECHO 15-inch freefloat Keymod handguard, full-length Picatinny top rail
• BCG and charging handle not included

Perfect For

• Builders sourcing a complete .450 Bushmaster AR-15 upper build kit with a Panhead billet upper receiver featuring an enlarged .458 ejection port, KAK .458 compensator, and Trinity Force ECHO Keymod 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 full-length Picatinny top rail Keymod handguard covered in one kit
• AR-15 builders who want a .450 Bushmaster upper build kit with a Panhead 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. The compensator is compatible with .458 and .450 Bushmaster at the 5/8x32 thread pitch. 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.

Panhead Billet Upper Receiver and Handguard

The Panhead billet aluminum upper receiver features an enlarged .458 pattern ejection port sized for the .450 Bushmaster cartridge, and an ejection port door with rod and spring. The Trinity Force ECHO 15-inch freefloat Keymod handguard features a full-length Picatinny top rail and Keymod 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.