Davidson Defense Ruin w/Gauntlet Arms Brace 10.5-inch Carbine-Gas 1:8 5.56 NATO AR-15 Freefloat M-Lok Handguard Pistol Full Build Kit

Ruin Gauntlet Arms Brace 10.5-inch Carbine-Gas 1:8 5.56 NATO AR-15 Freefloat M-LOK Pistol Full Build Kit, Right-Side Charging

The Ruin is a 5.56 NATO AR-15 Full Build Kit built around a compact 10.5-inch carbine-length gas platform with a dedicated right-side charging billet upper receiver. The kit centers on a 10.5-inch cryogenically treated Sandel steel barrel with a phosphate finish, 1:8 twist rate, and 1/2x28 thread pitch, paired with a salt bath nitride two-chamber muzzle brake and a black 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 billet 6061 aluminum right-side charging upper receiver carries a Type III hardcoat anodized finish and includes a timing plug, paired with a 10-inch freefloat M-LOK handguard in black. The Tactical Solutions Group side charging bolt carrier group with an included side charger BCG handle completes the upper side. The lower hardware includes a complete Mil-Spec AR-15 lower parts kit with a Mil-Spec AR-15 pistol grip, a heavy-duty AR-15 pistol buffer tube, a standard 3 oz carbine buffer, a standard carbine recoil spring, an AR-15 M16 Mil-Spec end plate, and an AR-15 carbine castle nut. The Gauntlet Arms polymer stabilizing brace in black is included. Lower receiver not included.

Key Features

• 10.5-inch cryogenically treated Sandel steel barrel, phosphate finish, 1:8 twist, 1/2x28 thread pitch, 5.56 NATO
• Carbine-length gas system
• Carbine-length stainless steel gas tube
• Micro low-profile steel gas block, 0.750
• Salt bath nitride two-chamber muzzle brake, 1/2x28, black crush washer included
• Billet 6061 aluminum right-side charging upper receiver, Type III hardcoat anodized, timing plug included
• 10-inch freefloat M-LOK handguard, black
• Tactical Solutions Group side charging bolt carrier group, side charger BCG handle included
• Complete Mil-Spec AR-15 lower parts kit, Mil-Spec AR-15 pistol grip included
• Heavy-duty AR-15 pistol buffer tube
• Standard carbine buffer, 3 oz
• Standard carbine recoil spring
• AR-15 M16 Mil-Spec end plate
• AR-15 carbine castle nut
• Gauntlet Arms polymer stabilizing brace, black

Perfect For

• Builders sourcing a complete 5.56 NATO AR-15 pistol full build kit with a dedicated right-side charging billet upper, cryogenically treated Sandel barrel, Tactical Solutions Group side charging BCG with handle, and Gauntlet Arms brace already included, pairing it with their own lower receiver
• Shooters building a compact 10.5-inch carbine-gas pistol platform who want the right-side charging bolt carrier group, salt bath nitride two-chamber muzzle brake, pistol buffer tube, and Gauntlet Arms brace covered in one kit
• AR-15 pistol builders who want a right-side charging billet upper with a timing plug and cryogenically treated barrel with a complete pistol buffer tube and lower parts kit without sourcing components separately

Barrel and Muzzle Device

The 10.5-inch Sandel barrel is chambered in 5.56 NATO and constructed from steel with a phosphate finish and cryogenic treatment. Cryogenic treatment subjects the barrel steel to deep cold temperatures to relieve residual stress in the metal structure. The twist rate is 1:8 and the thread pitch is 1/2x28, which matches the included salt bath nitride two-chamber muzzle brake. A black 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.

Right-Side Charging Billet Upper Receiver and Handguard

The billet 6061 aluminum upper receiver carries a Type III hardcoat anodized finish and is designed around a dedicated right-side charging system. A timing plug is included for the side-charging upper receiver. The 10-inch freefloat M-LOK handguard is black with 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 pistol platform.

Side Charging Bolt Carrier Group

The Tactical Solutions Group side charging bolt carrier group includes a side charger BCG handle and is designed specifically for use with right-side charging upper receiver platforms.

Lower Parts Kit and Buffer System

The complete Mil-Spec AR-15 lower parts kit covers the internal lower receiver components and includes a Mil-Spec AR-15 pistol grip. The buffer system includes a heavy-duty AR-15 pistol buffer tube, a standard 3 oz carbine buffer, a standard carbine recoil spring, an AR-15 M16 Mil-Spec end plate, and an AR-15 carbine castle nut. The Gauntlet Arms polymer stabilizing brace in black pairs with the included pistol buffer tube and covers the rear brace interface for this pistol lower build kit.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. Lower receiver not included. Verify local and state laws regarding pistol brace use and classification. This upper receiver accepts right-side charging bolt carrier groups only.