The Davidson Defense Marathon 14.5" Carbine AR-15 Pistol Full Build Kit is designed for dependable performance and precision in 5.56 NATO. It features a 14.5" government profile barrel made from 4150 CrMoV steel with a phosphate finish, a 1:7 twist rate, and a carbine-length gas system for smooth, consistent cycling. With 1/2x28 threads, the barrel is pin-and-weld ready—allowing the user to install a muzzle device to meet the 16" minimum length requirement. The upper receiver is built from 6061-T6 aluminum with a Type III hard coat anodized finish, paired with a 12" M-LOK handguard for versatile accessory mounting. The kit includes a Gauntlet Arms brace, heavy-duty pistol buffer tube, 3 oz buffer, standard carbine recoil spring, and a Recoil Technologies micro low-profile gas block—offering a complete foundation for a reliable and regulation-ready AR-15 build.
Barrel Length: 14.5-inch
Caliber: 5.56x45mm NATO
Barrel Material: 4150 CrMoV
Barrel Thread Pitch: 1/2x28
Gas System Length: Carbine
Barrel Finish: Phosphate
Barrel Profile: Government
Barrel Twist Rate: 1:7
Gas Block Size: 0.750
Gas Block Name: Recoil Technologies Micro Low-Profile Gas Block
Upper Receiver Material: 6061-T6 Aluminum
Upper Receiver Finish: Type III Hard Coat Anodized
Handguard Material: Aircraft-Grade Aluminum
Handguard Length: 12-inch
Handguard Style: M-LOK
Handguard Color: Black
Bolt Carrier Material: 9310 Alloy Steel (Bolt Head), 8620 Alloy Steel (Body)
Bolt Carrier Finish: Nitride
Charging Handle: AR-15 M4 Charging Handle Mil-Spec Quality
Pistol Brace : Polymer Stabilizing Brace - Black
Buffer Tube : Heavy Duty Pistol Buffer Tube for AR-15 and AR Style Pistols
Buffer Weight: 3 oz
Recoil Spring: Standard AR-15 Carbine Recoil Spring
End Plate Information: AR-15 M16 Mil-Spec Receiver End Plate
Castle Nut: AR-15 Carbine Castle Nut
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