This CMMG Barrel Sub-Assembly (brand part number 60D100C) lets builders run Hornady’s 6mm ARC cartridge on an AR-15 platform, machined from 416 stainless steel to a medium taper profile at 16.1 inches. CMMG threads the muzzle at 5/8-24 TPI to accept standard-pattern muzzle devices and times the assembly to a rifle-length gas system for smooth, reliable cycling with the 6mm ARC’s higher operating pressures. It’s a dedicated, purpose-built option for shooters who want to add 6mm ARC’s long-range performance to an existing AR-15 lower.

Key Specifications

• Chambered in 6mm ARC.
• Measures 16.1 inches in barrel length.
• Rifled with a 1:7.5 twist rate.
• Machined to a medium taper profile.
• Machined from 416 stainless steel.
• Threaded 5/8-24 TPI.
• Runs a rifle-length gas system.

Frequently Asked Questions

What gas system length does it use? Rifle-length.

What’s the twist rate? 1:7.5, tuned for 6mm ARC bullet weights.

What thread pattern is the muzzle? 5/8-24 TPI.

Buy the CMMG 6mm ARC Barrel Sub-Assembly

Add Hornady’s 6mm ARC performance to your next AR-15 build. Order it from our CMMG lineup, part of our AR barrels selection, at our Lubbock, Texas gun shop for direct shipping.