Davidson Defense Stone River 16.5-inch Mid-Gas 1:7 .223 Wylde AR-15 Freefloat M-Lok Handguard Rifle Upper Build Kit

Stone River 16.5-inch Mid-Gas 1:7 .223 Wylde AR-15 Freefloat M-LOK Upper Build Kit

The Stone River is a .223 Wylde AR-15 Upper Build Kit built around a 16.5-inch mid-length gas platform. The kit centers on a 16.5-inch 4150 steel barrel with a nitride finish, 1:7 twist rate, and 1/2x28 thread pitch, paired with an A2 GI birdcage flash hider and a black 1/2-inch crush washer. A micro low-profile steel gas block at 0.750 diameter and a mid-length stainless steel gas tube are included on the front end. The USA-made slick side billet 6061 aluminum upper receiver features an anti-rotation cutout and no forward assist housing, paired with a 15-inch freefloat M-LOK handguard in black with a partial Picatinny top rail section. BCG and charging handle are not included.

Key Features

• 16.5-inch 4150 steel barrel, nitride finish, 1:7 twist, 1/2x28 thread pitch, .223 Wylde
• Mid-length gas system
• Mid-length stainless steel gas tube
• Micro low-profile steel gas block, 0.750
• A2 GI birdcage flash hider, 1/2x28, black 1/2-inch crush washer included
• USA-made slick side billet 6061 aluminum upper receiver, anti-rotation cutout, no forward assist housing
• 15-inch freefloat M-LOK handguard, black, partial Picatinny top rail section
• BCG and charging handle not included

Perfect For

• Builders sourcing a complete .223 Wylde AR-15 upper build kit with a USA-made slick side billet upper featuring an anti-rotation cutout and a 15-inch freefloat M-LOK handguard with a partial Picatinny top rail, pairing it with their own bolt carrier group and charging handle
• Shooters building a 16.5-inch mid-gas .223 Wylde platform who prefer to select their own BCG while having the nitride barrel, USA-made slick side billet upper with anti-rotation cutout, and freefloat M-LOK handguard covered in one kit
• AR-15 builders who want a .223 Wylde upper build kit with a clean slick side billet upper, mid-length gas system, and 15-inch freefloat M-LOK handguard with a partial Picatinny top rail without sourcing components separately

Barrel and Muzzle Device

The 16.5-inch barrel is chambered in .223 Wylde and constructed from 4150 steel with a nitride finish. The twist rate is 1:7 and the thread pitch is 1/2x28, which matches the included A2 GI birdcage flash hider. A black 1/2-inch crush washer, a micro low-profile steel gas block at 0.750 diameter, and a mid-length stainless steel gas tube cover the front end gas configuration on this mid-length platform.

Slick Side Billet Upper Receiver and Handguard

The USA-made slick side billet 6061 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 handguard is black with a partial Picatinny top rail section 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.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. BCG and charging handle are not included.