Product Description The Sons of Liberty Gun Works M4-L89 Upper Receiver Group is a duty-ready, non-NFA upper assembly built for serious shooters. Featuring a 14.5-inch Liberty Fighting Barrel chambered in 5.56 NATO with a Pin and Welded Plan B Flash Hider, this upper achieves a legally compliant 16-inch overall barrel length without requiring an NFA short-barreled rifle registration. Optimized for users of the Rearden or Q Plan B mounting system, this upper pairs a forged mil-spec upper receiver with the L89 Drivelock handguard, which incorporates a titanium barrel nut and a high-strength locking interface to ensure that optics and accessories maintain precise zero under thermal stress and hard use. A mid-length gas system provides a balanced and smooth recoil impulse, making this configuration especially effective when shooting suppressed. Whether for competition, home defense, or duty use, the SOLGW M4-L89 URG delivers premium performance in a versatile, compliant package. Product Highlights 14.5" 5.56 NATO Liberty Fighting Barrel with Pin and Welded Plan B Flash Hider achieving a legal 16" overall barrel length 13.75" L89 Drivelock Handguard with titanium barrel nut and 7-sided M-LOK slots for versatile accessory mounting Forged mil-spec upper receiver ensuring durability and broad compatibility with standard AR-15 lower receivers Integral QD sling attachment points at the barrel nut on both sides for flexible sling configurations Mid-length gas system delivers reliable, balanced cycling performance, particularly effective in suppressed configurations Specs Brand: Sons of Liberty Gun Works MPN: U-M4L89-556-145-PB UPC: 657628673033 Caliber: 5.56 NATO Barrel Length: 14.5" Overall Barrel Length (Pinned and Welded): 16" Handguard: 13.75" L89 Muzzle Device: Plan B Flash Hider (Pinned and Welded) Gas System: Mid-Length Rail System: 7-Sided M-LOK Barrel Nut: Titanium Drivelock Finish: Matte Black Platform Compatibility: AR-15 Includes: Upper Receiver Group (Does Not Include BCG or Charging Handle) Disclaimer: We strive to provide accurate and up-to-date product descriptions, specifications, and images; however, errors or omissions may occasionally occur. We are not responsible for any inaccuracies or discrepancies in the content provided. If you notice anything incorrect or unclear, please contact us so we can correct it. When in doubt, we recommend verifying details directly with the product&';s manufacturer.