This full build kit combines a 14.5-inch 4150 CrMoV barrel with a 10-inch freefloat quad-rail handguard, chambered in 5.56 NATO. The kit includes an anodized 7075-T6 aluminum upper receiver with M4 feed ramps, micro low-profile gas block, carbine-length gas system, GI birdcage flash hider, mil-spec charging handle, 5.56x45mm QPQ nitride bolt carrier group, SB Tactical SBA5 pistol stabilizing brace, mil-spec heavy-duty 6-position buffer tube, 3 oz buffer, carbine recoil spring, castle nut, end plate, and complete mil-spec lower parts kit. Lower receiver not included.
5.56 NATO chambering provides compatibility with both 5.56 NATO and .223 Remington ammunition. The 1:7 twist rate stabilizes a wide range of bullet weights including heavier projectiles up to 77 grains.
The SB Tactical SBA5 pistol stabilizing brace features nylon reinforced polymer construction with adjustable positioning. The brace pairs with the included mil-spec heavy-duty 6-position buffer tube, 3 oz buffer, carbine recoil spring, castle nut, and end plate.
The 10-inch freefloat quad-rail handguard provides 6061-T6 aluminum construction with continuous Picatinny rails on all four sides for maximum accessory mounting flexibility. The freefloat design isolates the barrel from external pressure, supporting accuracy.
The 5.56x45mm bolt carrier group features QPQ nitride finish over 9310 alloy steel. The nitride treatment provides corrosion resistance and surface hardness while reducing friction.
This full build kit is compatible with mil-spec AR-15 lower receivers. All components use standard AR-15 specifications and threading, including the 1/2x28 TPI muzzle threads matching the included GI birdcage flash hider.
Lower receiver not included. Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws.
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
Muzzle Device Model: AR-15 TPI GI Birdcage Flash Hider
Muzzle Thread Pitch: 1/2x28
Gas System Length: Carbine
Gas Block Name: Micro Low-Profile Gas Block
Gas Block Material: Steel
Gas Block Size: 0.750
Handguard Length: 10 inches
Handguard Material: 6061-T6 Aluminum
Handguard Color: Black
Handguard Style: Free Float Quad Rail
Upper Receiver Material: 7075 T6 Aluminum
Upper Receiver Finish: Anodized
Charging Handle Material: Aluminum
Bolt Carrier Material: 9310 Alloy Steel
Bolt Carrier Finish: Nitride
Buffer Material: Aluminum
Recoil Buffer Weight: 3 oz
Lower Parts Kit: Mil-Spec AR-15 Lower Parts Kit
Brace Model: SB Tactical SBA5 Pistol Stabilizing Brace
Brace Color: Black
Brace Material: Nylon Reinforced Polymer
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