The LMT Monolithic .300 AAC Blackout 10.5” Pistol-Length Barrel in Black (LMT part no. R-L7BH1B) is a factory-spec barrel built for LMT’s MRP monolithic upper receiver platform, chambered in .300 AAC Blackout for a short, maneuverable AR15 pistol build. The pistol-length gas system is tuned for reliable cycling on a shorter platform, and the 1-in-7 twist stabilizes the full range of .300 Blackout bullet weights, from lightweight supersonic loads to heavy subsonic rounds. This barrel length and cartridge combination is a popular choice for suppressed pistol builds and close-quarters use. LMT manufactures it to the same spec used on its complete rifles.

Key Specifications

• Measures 10.5 inches long, sized for a compact .300 Blackout pistol build.
• Chambered in .300 AAC Blackout, a cartridge suited to both supersonic and subsonic loads.
• Rifled with a 1-in-7 twist, stabilizing the full range of .300 Blackout bullet weights.
• Built for the LMT MRP monolithic upper platform, and finished in black.
• Paired with a pistol-length gas system tuned for reliable cycling at this barrel 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

Why is .300 Blackout popular for short-barrel builds? It’s designed to run efficiently out of short barrels and to cycle reliably with both supersonic and subsonic ammunition, including when suppressed.

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 .300 AAC Blackout 10.5-inch Pistol-Length Barrel, Black

Shop the LMT Defense .300 Blackout barrel in our AR barrels selection, with fast, insured shipping from our Lubbock, Texas gun shop.