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

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

The Lochness 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 CMV steel with a phosphate finish, 1:24 twist rate, and 5/8x32 thread pitch, paired with a KAK .458 compensator compatible with .458 SOCOM 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, paired with a 15-inch Trinity Force ECHO freefloat Keymod handguard with a full-length Picatinny top rail. A complete .458 SOCOM and .450 Bushmaster compatible bolt carrier group 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 carbine buffer tube, a standard 3 oz carbine buffer, a standard AR-15 carbine recoil spring, a Mil-Spec AR-15 and M16 end plate, and a Mil-Spec AR-15 carbine castle nut. The AR-15 Ranger A-frame adjustable stock in black with integrated QD sling mounts rounds out the kit. Lower receiver 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 SOCOM and .450 Bushmaster compatible, black crush washer included
• Panhead billet aluminum upper receiver, enlarged .458 pattern ejection port
• Trinity Force ECHO 15-inch freefloat Keymod handguard, full-length Picatinny top rail
• Complete .458 SOCOM and .450 Bushmaster bolt carrier group
• Mil-Spec AR-15 M4 charging handle
• Complete Mil-Spec AR-15 lower parts kit
• Mil-Spec heavy-duty 6-position carbine buffer tube
• Standard carbine buffer, 3 oz
• Standard AR-15 carbine recoil spring
• Mil-Spec AR-15 and M16 end plate
• Mil-Spec AR-15 carbine castle nut
• AR-15 Ranger A-frame adjustable stock, black, integrated QD sling mounts, Mil-Spec carbine buffer tube compatible

Perfect For

• Builders sourcing a complete .450 Bushmaster AR-15 full build kit with a Panhead billet upper receiver, KAK .458 compensator, compatible BCG, Trinity Force ECHO Keymod handguard, and Ranger A-frame stock with integrated QD sling mounts 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, complete lower parts kit, and buffer system covered in one kit with a full-length Picatinny top rail Keymod handguard
• 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 Ranger A-frame stock with integrated QD sling mounts 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 SOCOM 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. 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.

Bolt Carrier Group and Charging Handle

The complete bolt carrier group 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 carbine buffer tube, a standard 3 oz carbine buffer, a standard AR-15 carbine recoil spring, a Mil-Spec AR-15 and M16 end plate, and a Mil-Spec AR-15 carbine castle nut. The AR-15 Ranger A-frame adjustable stock in black features integrated QD sling mounts and pairs with the included Mil-Spec carbine buffer tube, covering 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.