Sons of Liberty Gun Works M4-EXO3 Barreled Upper 5.56 14.5" Mid-Length Plan B

The Sons of Liberty Gun Works M4-EXO3 Barreled Upper is a duty-grade, non-NFA upper receiver group optimized for users of the Rearden or Q Plan B mounting ecosystem. It features a 14.5-inch Liberty Fighting Barrel (4150 CrMoV) with a mid-length gas system, providing a smoother recoil impulse and reduced wear on internal parts. To reach the legal 16-inch minimum barrel length for standard rifles without NFA registration, a Plan B-compatible flash hider is permanently pinned and welded (P& W) to the muzzle. Built on a forged 7075-T6 aluminum upper, this assembly includes the EXO3 handguard, which offers a slim, lightweight seven-sided M-LOK mounting platform and a robust steel barrel nut for enhanced stability. Sons of Liberty Gun Works M4-EXO3 5.56mm 14.5" Bbl Mid Gas EXO3 Rail P& W Plan BFH Liberty Fighting Bbl & Mil-Spec Upper Receiver U-M4EXO3-556-145-PB