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

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

The Invictus 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 Sepal 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 Panhead billet aluminum design configured for .458 SOCOM and .450 Bushmaster with an enlarged .458 ejection port door installed and an ejection port door, rod, and spring included, paired with a 15-inch freefloat M-LOK handguard in black with a partial Picatinny rail section. 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 with a fire control group and a Mil-Spec A2 style pistol grip in black, a heavy-duty 6-position aluminum carbine buffer tube, a standard 3 oz carbine buffer, a USA-made standard carbine recoil spring, an AR-15 M16 Mil-Spec end plate, and an AR-15 carbine castle nut. The Mil-Spec enhanced adjustable stock in black with a polymer cheek riser and rubberized recoil pad rounds out the kit. Lower receiver not included.

Key Features

• 18-inch Sepal 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
• Panhead billet aluminum upper receiver, .458 SOCOM and .450 Bushmaster compatible, enlarged .458 ejection port door installed, ejection port door, rod, and spring included
• 15-inch freefloat M-LOK handguard, black, partial Picatinny rail section
• Complete .458 SOCOM and .450 Bushmaster bolt carrier group
• Mil-Spec AR-15 M4 charging handle
• Complete Mil-Spec AR-15 lower parts kit, fire control group included, Mil-Spec A2 style pistol grip, black
• Heavy-duty 6-position aluminum carbine buffer tube
• Standard carbine buffer, 3 oz
• Standard carbine recoil spring, made in USA
• AR-15 M16 Mil-Spec end plate
• AR-15 carbine castle nut
• Mil-Spec enhanced adjustable stock, black, polymer cheek riser, rubberized recoil pad

Perfect For

• Builders sourcing a complete .450 Bushmaster AR-15 full build kit with a Panhead billet upper receiver, Sepal HBAR barrel, KAK .458 compensator, compatible BCG, and enhanced adjustable stock with polymer cheek riser and rubberized recoil pad 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 enhanced stock with cheek riser and recoil pad covered in one kit
• 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 compatible BCG without sourcing components separately

Barrel and Muzzle Device

The 18-inch Sepal 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.

Panhead Billet Upper Receiver and Handguard

The Panhead billet aluminum upper receiver is configured for .458 SOCOM and .450 Bushmaster with an enlarged .458 ejection port door installed. An ejection port door, rod, and spring are included. The 15-inch freefloat M-LOK handguard is black with a partial Picatinny rail section and M-LOK 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 and includes a fire control group and a Mil-Spec A2 style pistol grip in black. The buffer system includes a heavy-duty 6-position aluminum carbine buffer tube, a standard 3 oz carbine buffer, a USA-made standard carbine recoil spring, an AR-15 M16 Mil-Spec end plate, and an AR-15 carbine castle nut. The Mil-Spec enhanced adjustable stock in black features a polymer cheek riser for cheekweld height adjustment and a rubberized recoil pad at the rear contact surface, pairing with the included carbine buffer tube and 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.