Sons of Liberty Gun Works L89 Barreled AR-15 Upper Receiver - 5.56 - 12.5" - A2

The Sons of Liberty Gun Works L89 Barreled AR-15 Upper Receiver in 5.56 NATO builds on the EXO3 platform with the Drivelock barrel nut, integral steel QD cups, and an internal dowel pin between upper and rail — a more rigid 12.5" build for duty operators running lasers or VAS systems.

Features:

• 12.5" Liberty Fighting Barrel chambered in 5.56 NATO
• Carbine-length gas system with 4140 steel gas block, nitrided gas tube
• Forged mil-spec upper receiver
• 11.75" L89 M-LOK handguard, seven-sided, Drivelock barrel nut
• Integral steel QD cups at the barrel nut, both sides
• Internal dowel pin between upper receiver and rail
• Muzzle comes with a A2 flash hider installed
• Test fired before shipment
• Bolt carrier group and charging handle not included

The Drivelock barrel nut gives more consistent, repeatable torque than a standard barrel nut, and the internal dowel pin locks the handguard's position independent of the barrel nut alone — together minimizing the point-of-impact shift that rail-mounted lasers and VAS systems can otherwise introduce. Integral steel QD cups on both sides give hardened sling attachment without a separate socket.

Since that muzzle device isn't pinned and welded, this 12.5" barrel must be built as an NFA-regulated short-barreled rifle or AR pistol, not a standard rifle.

Sons of Liberty Gun Works builds and test-fires every rifle and barreled upper in the United States, applying the same standards to individual components as they do to their complete rifles.