Davidson Defense Halcyon w/SBA3 Brace 10.5-inch Pistol-Gas 1:8 .300 BLK AR-15 Freefloat M-Lok Handguard Pistol Full Build Kit

Halcyon SBA3 Brace 10.5-inch Pistol-Gas 1:8 .300 BLK AR-15 Freefloat M-LOK Pistol Full Build Kit

The Halcyon is a .300 Blackout AR-15 Full Build Kit built around a compact 10.5-inch pistol-length gas platform. The kit centers on a 10.5-inch HBAR profile parkerized barrel with a 1:8 twist rate and 5/8x24 thread pitch, paired with a Steel Flash Can Design 4 in black oxide and a black 5/8-inch crush washer. 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 12-inch MX10 freefloat M-LOK handguard. A USA-made complete 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 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

• 10.5-inch HBAR profile parkerized 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
• Steel Flash Can Design 4, black oxide finish, 5/8x24, black 5/8-inch crush washer included
• 7075-T6 aluminum upper receiver, anodized, M4 feed ramps, forward assist, ejection port door assembly
• 12-inch MX10 freefloat M-LOK handguard
• USA-made complete 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
• 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 10.5-inch HBAR parkerized barrel, 7075-T6 anodized upper receiver with forward assist, USA-made BCG compatible with multiple calibers, 12-inch MX10 freefloat M-LOK handguard, and SBA3 adjustable brace on a 6-position carbine buffer tube already included, pairing it with their own lower receiver
• Shooters building a compact 10.5-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 an MX10 freefloat M-LOK handguard
• AR-15 pistol builders who want a .300 Blackout full build kit with a USA-made BCG compatible with multiple calibers and an SBA3 adjustable brace without sourcing components separately

Barrel and Muzzle Device

The 10.5-inch HBAR profile barrel is chambered in .300 Blackout with a parkerized finish, 1:8 twist rate, and 5/8x24 thread pitch, which matches the included Steel Flash Can Design 4 in black oxide. A black 5/8-inch crush washer, 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 12-inch MX10 freefloat M-LOK handguard features 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 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 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 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.