The Davidson Defense Marathon 14.5" Carbine-Gas 5.56 NATO AR-15 Pistol Upper Build Kit is built for strength, reliability, and performance. It features a 14.5" 4150 CrMoV steel barrel with a phosphate finish, government profile, 1:7 twist rate, and a carbine-length gas system for consistent cycling. The 6061-T6 aluminum upper receiver and aircraft-grade M-LOK handguard offer lightweight durability and accessory compatibility. With a 0.750 gas block size and 1/2x28 thread pitch, this kit is ideal for builders looking to pin and weld their own muzzle device to meet the legal 16" overall barrel length requirement—making it a ready platform for compliant rifle builds.
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
Gas Block Finish: Phosphate
Gas Block Material: Steel
Upper Receiver Material: 6061-T6 Aluminum
Upper Receiver Finish: Anodized
Handguard Material: Aircraft-Grade Aluminum
Handguard Color: Black
Handguard Style: M-LOK
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