Davidson Defense Silent Guardian w/SBA3 Brace 7.5-inch Pistol-Gas 1:8 .300 BLK AR-15 Freefloat M-Lok Handguard Pistol Full Build Kit, Plan B Radial Brake

Silent Guardian SBA3 Brace 7.5-inch Pistol-Gas 1:8 .300 BLK AR-15 Freefloat M-LOK Pistol Full Build Kit, Plan B Radial Brake

The Silent Guardian is a .300 Blackout AR-15 Full Build Kit built around a compact 7.5-inch pistol-length gas platform. The kit centers on a 7.5-inch HBAR profile phosphate barrel with a 1:8 twist rate and 5/8x24 thread pitch, paired with the Delta Team Tactical Plan B radial hole muzzle brake in black nitride 17-4 H1150 stainless steel. A micro low-profile steel gas block at 0.750 diameter and a pistol-length gas tube are included on the front end. The 7075-T6 aluminum anodized upper receiver features M4 feed ramps, a forward assist, and an ejection port door assembly, paired with a 7-inch freefloat M-LOK handguard in black. A USA-made complete AR-15 bolt carrier group compatible with 5.56 NATO, .223 Remington, .300 Blackout, and .350 Legend, and a Mil-Spec AR-15 M4 charging handle complete the upper side. The lower hardware includes a complete Mil-Spec AR-15 lower parts kit, a Mil-Spec heavy-duty 6-position aluminum carbine buffer tube, a standard 3 oz AR-15 carbine buffer, a USA-made standard AR-15 carbine recoil spring, a Mil-Spec AR-15 M16 receiver end plate, and an AR-15 carbine castle nut. The SB Tactical SBA3 adjustable pistol stabilizing brace in black is included. Lower receiver not included.

Key Features

• 7.5-inch HBAR profile phosphate barrel, 1:8 twist, 5/8x24 thread pitch, .300 Blackout
• Pistol-length gas system
• Pistol-length gas tube
• Micro low-profile steel gas block, 0.750
• Delta Team Tactical Plan B radial hole muzzle brake, black nitride 17-4 H1150 stainless steel, 5/8x24
• Plan B muzzle brake supports modular suppressor mounting ecosystems
• 7075-T6 aluminum upper receiver, anodized, M4 feed ramps, forward assist, ejection port door assembly
• 7-inch freefloat M-LOK handguard, black
• USA-made complete AR-15 bolt carrier group, 5.56 NATO and .223 Remington and .300 Blackout and .350 Legend compatible
• Mil-Spec AR-15 M4 charging handle
• Complete Mil-Spec AR-15 lower parts kit
• Mil-Spec heavy-duty 6-position aluminum carbine buffer tube
• Standard AR-15 carbine buffer, 3 oz
• Standard AR-15 carbine recoil spring, made in USA
• Mil-Spec AR-15 M16 receiver end plate
• AR-15 carbine castle nut
• SB Tactical SBA3 adjustable pistol stabilizing brace, black

Perfect For

• Builders sourcing a complete .300 Blackout AR-15 pistol full build kit with a 7.5-inch HBAR phosphate barrel, 7075-T6 anodized upper receiver with forward assist, USA-made BCG compatible with multiple calibers, 7-inch freefloat M-LOK handguard, Delta Team Tactical Plan B radial hole muzzle brake, and SBA3 adjustable brace on a Mil-Spec carbine buffer tube already included, pairing it with their own lower receiver
• Shooters building a compact 7.5-inch pistol-gas .300 Blackout platform who want the USA-made BCG, charging handle, complete lower parts kit, and SBA3 adjustable brace covered in one kit with a Plan B radial hole muzzle brake supporting modular suppressor mounting
• AR-15 pistol builders who want a .300 Blackout full build kit with a USA-made BCG compatible with multiple calibers, a Delta Team Tactical Plan B radial hole muzzle brake, and an SBA3 adjustable brace without sourcing components separately

Barrel and Plan B Radial Hole Muzzle Brake

The 7.5-inch HBAR profile barrel is chambered in .300 Blackout with a phosphate finish, 1:8 twist rate, and 5/8x24 thread pitch, which matches the included Delta Team Tactical Plan B radial hole muzzle brake. The Plan B muzzle brake is 17-4 H1150 stainless steel with a black nitride finish and supports modular suppressor mounting ecosystems. A micro low-profile steel gas block at 0.750 diameter and a pistol-length gas tube cover the front end gas configuration on this pistol-length platform.

Upper Receiver and Handguard

The 7075-T6 aluminum upper receiver carries an anodized finish with M4 feed ramps, a forward assist, and an ejection port door assembly. The 7-inch freefloat M-LOK handguard is black with M-LOK attachment points along the body for accessory mounting. These two components define the exterior structure of the upper assembly on this AR-15 pistol platform.

Bolt Carrier Group and Charging Handle

The USA-made complete AR-15 bolt carrier group is compatible with 5.56 NATO, .223 Remington, .300 Blackout, and .350 Legend. A Mil-Spec AR-15 M4 charging handle is included to complete the upper component set.

Lower Parts Kit and Buffer System

The complete Mil-Spec AR-15 lower parts kit covers the internal lower receiver components. The buffer system includes a Mil-Spec heavy-duty 6-position aluminum carbine buffer tube, a standard 3 oz AR-15 carbine buffer, a USA-made standard AR-15 carbine recoil spring, a Mil-Spec AR-15 M16 receiver end plate, and an AR-15 carbine castle nut. The SB Tactical SBA3 adjustable pistol stabilizing brace in black pairs with the included Mil-Spec carbine buffer tube and covers the rear brace interface for this pistol lower build kit.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. Lower receiver not included. Verify local and state laws regarding pistol brace use and classification.