Davidson Defense Vaultmaster 16-inch Carbine-Gas 1:16 .350 Legend AR-15 Freefloat Keymod Handguard Rifle Upper Build Kit

Vaultmaster 16-inch Carbine-Gas 1:16 .350 Legend AR-15 Freefloat Keymod Upper Build Kit

The Vaultmaster is a .350 Legend AR-15 Upper Build Kit built around a 16-inch carbine-length gas platform. The kit centers on a 16-inch M4 profile steel barrel with a phosphate finish, 1:16 twist rate, and 5/8x24 thread pitch, paired with a GI birdcage flash hider compatible with .350 Legend, .308 Win, 7.62x39, and .300 Blackout, and a black 5/8-inch crush washer. A micro low-profile steel gas block at 0.750 diameter and a carbine-length stainless steel gas tube are included on the front end. The upper receiver is a USA-made billet aluminum slick side design with an anti-rotation cutout and no forward assist, paired with a 15-inch Trinity Force KMX freefloat Keymod handguard in black aluminum with a full-length Picatinny top rail. BCG and charging handle are not included.

Key Features

• 16-inch M4 profile steel barrel, phosphate finish, 1:16 twist, 5/8x24 thread pitch, .350 Legend
• Carbine-length gas system
• Carbine-length stainless steel gas tube
• Micro low-profile steel gas block, 0.750
• GI birdcage flash hider, 5/8x24, .350 Legend and .308 Win and 7.62x39 and .300 Blackout compatible, black crush washer included
• USA-made billet aluminum slick side upper receiver, anti-rotation cutout, no forward assist
• Trinity Force KMX 15-inch freefloat Keymod handguard, black aluminum, full-length Picatinny top rail
• BCG and charging handle not included

Perfect For

• Builders sourcing a complete .350 Legend AR-15 upper build kit with a USA-made billet slick side upper and Trinity Force KMX Keymod handguard, pairing it with their own bolt carrier group and charging handle
• Shooters building a 16-inch .350 Legend carbine-gas platform who prefer to select their own BCG while having the phosphate barrel, compatible muzzle device, and slick side billet upper covered in one kit
• AR-15 builders who want a Trinity Force KMX 15-inch freefloat Keymod handguard with a full-length Picatinny top rail on a USA-made slick side billet upper without sourcing components separately

Barrel and Muzzle Device

The 16-inch M4 profile barrel is chambered in .350 Legend and constructed from steel with a phosphate finish. The twist rate is 1:16 and the thread pitch is 5/8x24, which matches the included GI birdcage flash hider. The flash hider is compatible with .350 Legend, .308 Win, 7.62x39, and .300 Blackout at the 5/8x24 thread pitch. A black 5/8-inch crush washer, a micro low-profile steel gas block at 0.750 diameter, and a carbine-length stainless steel gas tube cover the front end gas configuration on this carbine-length platform.

Slick Side Billet Upper Receiver and Handguard

The USA-made billet aluminum slick side upper receiver features an anti-rotation cutout and removes the forward assist housing from the upper receiver body for a clean exterior profile. The Trinity Force KMX 15-inch freefloat Keymod handguard is black aluminum with 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 .350 Legend platform.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. BCG and charging handle are not included.