The Davidson Defense Marathon 14.5" Carbine-Gas 5.56 NATO AR-15 Pistol Full Build Kit with SBA3 Brace includes everything needed for a reliable, pin-and-weld ready build. The 14.5" government profile barrel is made from 4150 CrMoV steel with a phosphate finish, 1:7 twist rate, and 1/2x28 threading—ready for the user to install and pin a muzzle device to meet the 16" legal length requirement. It features a carbine-length gas system with a 0.750 gas block for smooth cycling. The 6061-T6 aluminum upper receiver is Type III hard coat anodized, and the aircraft-grade aluminum M-LOK handguard provides durable, lightweight accessory mounting. The kit includes a nitride-finished Recoil Technologies Premium Bolt Carrier Group and an SB Tactical SBA3 adjustable stabilizing brace for improved control and handling—making it a solid foundation for a compliant, high-performance AR-15 build.
Caliber: 5.56x45mm NATO
Barrel Length: 14.5-inch
Barrel Material: 4150 CrMoV
Barrel Thread Pitch: 1/2x28
Barrel Finish: Phosphate
Barrel Profile: Government
Barrel Twist Rate: 1:7
Barrel Gas System Length: Carbine
Gas Block Size: 0.750
Bolt Carrier: Recoil Technologies Premium Complete Bolt Carrier Group
Bolt Carrier Material: 9310 Alloy Steel
Bolt Carrier Finish: Nitride
Upper Receiver Material: 6061-T6 Aluminum
Upper Receiver Finish: Type III Hard Coat Anodized
Handguard Material: Aircraft-Grade Aluminum
Handguard Color: Black
Handguard Style: M-LOK
Pistol Brace Information: SB Tactical SBA3 Adjustable Pistol Stabilizing Brace
Charging Handle: AR-15 M4 Charging Handle Mil-Spec Quality
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