The LMT Monolithic 5.56×45 NATO 14.5” Mid-Length Barrel in Black (LMT part no. R-L7NE1B) is a factory-spec barrel built for LMT’s MRP monolithic upper receiver platform, pairing a 14.5-inch length with a mid-length gas system for smoother cycling than a standard carbine-length setup. This is the barrel length used on many pinned-and-welded rifle-length AR15 builds that keep overall configuration under 16 inches of barrel with a permanently attached muzzle device. The 1-in-7 twist stabilizes heavier 5.56 NATO bullets used in duty and match ammunition. LMT manufactures this barrel to the same tolerances used on its complete contract rifles.

Key Specifications

• Measures 14.5 inches long with a mid-length gas system for smoother cycling.
• Chambered in 5.56×45 NATO, the standard AR15 platform cartridge.
• Rifled with a 1-in-7 twist, stabilizing heavier NATO-spec 5.56 bullets.
• Built for the LMT MRP monolithic upper platform, and finished in black.
• Paired with a mid-length gas system for a smoother cycling impulse than carbine-length.
• Compatible with LMT’s MRP monolithic upper receiver platform.
• Uses a standard barrel extension compatible with mil-spec 5.56 bolt carrier groups.

Frequently Asked Questions

Is a 14.5-inch barrel NFA-regulated on a rifle build? Barrels under 16 inches on a rifle-configured receiver generally require NFA registration unless a muzzle device is permanently attached to bring total length to 16 inches or more; confirm your configuration before assembly.

Does this barrel fit LMT’s own upper receivers? Yes, it’s built to mate with the LMT MRP monolithic upper receiver system.

Buy the LMT Monolithic 5.56 NATO 14.5-inch Mid-Length Barrel, Black

Shop the LMT Defense 14.5-inch barrel in our AR barrels selection, with fast, insured shipping from our Lubbock, Texas gun shop.