Davidson Defense Darkstar 18-inch Rifle-Gas 1:7.5 6mm ARC AR-15 Freefloat M-Lok Handguard Rifle Complete Upper Build

Darkstar 18-inch Rifle-Gas 1:7.5 6mm ARC AR-15 Freefloat M-LOK Extended Quad Rail Rifle Complete Upper

The Darkstar is a 6mm ARC AR-15 Complete Upper built around an 18-inch rifle-length gas platform. The kit centers on an 18-inch government profile 41V50 CrMoV steel barrel with a nitride finish, 5R rifling, 1:7.5 right-hand twist rate, and 5/8x24 thread pitch, paired with a GI birdcage flash hider and a black 5/8-inch crush washer. A micro low-profile steel gas block at 0.750 diameter and a rifle-length stainless steel gas tube are included on the front end. The USA-made 6061 slick side billet aluminum upper receiver features an anti-rotation cutout, paired with a 15-inch freefloat M-LOK extended quad rail handguard in black with a clamp-on G-style design. A complete AR-15 6.5 Grendel II bolt carrier group with QPQ nitride finish and a Mil-Spec AR-15 M4 charging handle complete the upper component set.

Key Features

• 18-inch government profile 41V50 CrMoV steel barrel, nitride finish, 5R rifling, 1:7.5 right-hand twist, 5/8x24 thread pitch, 6mm ARC
• Rifle-length gas system
• Rifle-length stainless steel gas tube
• Micro low-profile steel gas block, 0.750
• GI birdcage flash hider, 5/8x24, black 5/8-inch crush washer included
• USA-made 6061 slick side billet aluminum upper receiver, anti-rotation cutout
• 15-inch freefloat M-LOK extended quad rail handguard, black, clamp-on G-style design
• Complete AR-15 6.5 Grendel II bolt carrier group, QPQ nitride finish
• Mil-Spec AR-15 M4 charging handle

Perfect For

• Builders sourcing a complete 6mm ARC AR-15 upper with an 18-inch 41V50 CrMoV nitride barrel with 5R rifling, USA-made slick side billet upper receiver with anti-rotation cutout, 6.5 Grendel II QPQ nitride BCG, and 15-inch freefloat M-LOK extended quad rail handguard in a clamp-on G-style design ready to pair with their own lower receiver
• Shooters building an 18-inch rifle-gas 6mm ARC platform who want the 6.5 Grendel II BCG and charging handle covered in one complete upper with a USA-made slick side billet upper receiver and 5R rifled nitride barrel
• AR-15 builders who want a 6mm ARC complete upper with a 6.5 Grendel II QPQ nitride BCG, USA-made slick side billet upper with anti-rotation cutout, and a 15-inch freefloat M-LOK extended quad rail handguard without sourcing components separately

Barrel and Muzzle Device

The 18-inch government profile barrel is chambered in 6mm ARC and constructed from 41V50 CrMoV steel with a nitride finish and 5R rifling. The twist rate is 1:7.5 right-hand and the thread pitch is 5/8x24, which matches the included GI birdcage flash hider. A black 5/8-inch crush washer, a micro low-profile steel gas block at 0.750 diameter, and a rifle-length stainless steel gas tube cover the front end gas configuration on this rifle-length platform.

Upper Receiver and Handguard

The USA-made 6061 slick side billet aluminum upper receiver features an anti-rotation cutout and removes the forward assist housing from the upper receiver body for a clean exterior profile. The 15-inch freefloat M-LOK extended quad rail handguard is black with a clamp-on G-style design and 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 platform.

Bolt Carrier Group and Charging Handle

The complete AR-15 6.5 Grendel II bolt carrier group carries a QPQ nitride finish and is compatible with the 6mm ARC platform. A Mil-Spec AR-15 M4 charging handle is included to complete the upper component set.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. Verify compatibility with your specific 6mm ARC lower receiver before use.