The Davidson Defense Marathon 14.5" Carbine-Gas 5.56 NATO AR-15 Pistol Full Build Kit with SBA5 Brace is built for precision, durability, and reliable performance. It features a 14.5" 4150 CrMoV barrel with a phosphate finish, government profile, 1:7 twist rate, and 1/2x28 threading—pin-and-weld ready for users needing to meet the 16" overall barrel length requirement. The carbine-length gas system and 0.750 gas block ensure smooth cycling. The upper receiver and M-LOK handguard are constructed from 6061-T6 aluminum and finished with Type III hard coat anodizing for long-lasting protection. The kit includes a nitride-finished 9310 steel bolt carrier group, standard M4 charging handle, SB Tactical SBA5 stabilizing brace, and a heavy-duty 6-position buffer tube—offering a complete, high-quality foundation for your next 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
Upper Receiver Material: 6061-T6 Aluminum
Upper Receiver Finish: Type III Hard Coat Anodized
Handguard Material: 6061-T6 Aluminum
Handguard Color: Black
Handguard Style: M-Lok
Charging Handle: AR-15 M4 Charging Handle Mil-Spec Quality
Bolt Carrier Material: 9310 Alloy Steel
Bolt Carrier Finish: Nitride
Pistol Brace: SB Tactical SBA5 Pistol Stabilizing Brace
Brace Material: Nylon Reinforced Polymer
Brace Color: Black
Buffer Tube: Mil-Spec Heavy-Duty AR-15 6-Position Buffer Tube
Buffer Weight: Standard 3 oz Carbine Recoil Buffer
Buffer Spring: Standard AR-15 Carbine Recoil Spring
Endplate: AR-15 M16 Mil-Spec Receiver End Plate
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