Davidson Defense Stardust 300 w/SBA5 Brace 8.5-inch Pistol-Gas 1:8 .300 BLK AR-15 Freefloat Quad-Rail Handguard Pistol Full Build Kit

Davidson Defense Stardust 300 8.5-inch Pistol-Gas 1-in-8 .300 Blackout AR-15 Freefloat Quad-Rail Full Build Kit with SBA5 Brace

The Stardust 300 Full Build Kit from Davidson Defense is a .300 Blackout AR-15 pistol configuration built around an 8.5-inch heavy-profile barrel with a pistol-length gas system. The kit includes the upper assembly, a bolt carrier group, charging handle, SB Tactical SBA5 pistol stabilizing brace, lower parts kit, and buffer system components. The lower receiver is not included.

Key Features

• .300 Blackout chambering with 8.5-inch heavy-profile pistol-gas barrel
• 4150 Chrome Moly Vanadium barrel with Parkerized finish and 1-in-8 twist rate
• 5-in-8x24 thread pitch with 6061-T6 aluminum muzzle-mounted fake can
• Panhead billet upper receiver, 6061-T6 aluminum with anodized finish
• Black anodized 6061-T6 aluminum 10-inch freefloat quad-rail handguard
• Micro low-profile steel gas block, .750 O.D.
• 9310 alloy steel bolt carrier group with nitride finish
• Mil-Spec M4 charging handle
• SB Tactical SBA5 pistol stabilizing brace, nylon reinforced polymer, black
• Heavy-duty 6-position aluminum buffer tube with 3 oz standard carbine buffer
• Standard AR-15 carbine recoil spring, Mil-Spec receiver end plate, and castle nut included
• Complete Mil-Spec lower parts kit included

Perfect For

• .300 Blackout AR-15 pistol builds
• Compact 8.5-inch barrel configurations in .300 Blackout
• Builders completing a stripped lower receiver
• Quad-rail handguard builds with full-length rail surface
• Pistol configurations with an adjustable stabilizing brace

Panhead Barrel and Upper Receiver

The barrel runs 8.5 inches in .300 Blackout with a 1-in-8 twist rate, heavy profile, and 4150 Chrome Moly Vanadium construction with a Parkerized finish. The pistol-length gas system pairs with a .750 O.D. micro low-profile steel gas block. The Panhead billet upper receiver is 6061-T6 aluminum with an anodized finish. Thread pitch is 5-in-8x24, and the kit includes a 6061-T6 aluminum muzzle-mounted fake can.

Handguard

The 10-inch freefloat quad-rail handguard is 6061-T6 aluminum with a black anodized finish. The quad-rail profile provides full-length rail surface on all four sides for accessory placement across the entire forend. At 10 inches, the handguard length exceeds the 8.5-inch barrel, so the barrel does not protrude past the handguard, with the muzzle device providing clearance forward of the handguard end.

Bolt Carrier Group and Charging Handle

The included bolt carrier group covers the 5.56, .223, .300, and .350 platform family and is 9310 alloy steel with a nitride finish. A Mil-Spec M4 charging handle completes the upper component set.

SB Tactical SBA5 Pistol Stabilizing Brace

The kit includes the SB Tactical SBA5 pistol stabilizing brace in black, constructed from nylon reinforced polymer. The SBA5 pairs with the included heavy-duty 6-position buffer tube and provides the rear interface for this pistol configuration.

Buffer System and Lower Components

The kit includes a heavy-duty 6-position aluminum buffer tube, a 3 oz standard carbine buffer, a standard AR-15 carbine recoil spring, a Mil-Spec receiver end plate, and a castle nut. A complete Mil-Spec lower parts kit covers the internal lower receiver components required for lower completion. These components cover the full lower completion hardware outside the serialized receiver itself.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. Lower receiver not included.