The CMMG 16.1-inch 5.56 Midlength Barrel Sub-Assembly, Medium Taper (brand part no. 55DC70A) is ideal for building a custom AR-15 upper group. CMMG machines it from 4140 chromoly steel with a black nitride finish, cuts it to a medium taper contour, and pairs it with a midlength gas system for a smooth recoil impulse on a 16.1-inch barrel. It ships with the M4 barrel extension already properly installed, saving builders a separate fitting step. For builders assembling a general-purpose 5.56 AR-15 upper, this AR barrel is ready to install.

Key Specifications

• Chambered in 5.56x45mm NATO.
• Barrel length measures 16.1 inches.
• Rifling twist is 1:7.
• Finished with a black nitride coating for corrosion resistance.
• Machined from 4140 chromoly steel.
• Built with a midlength gas system.
• Cut in a medium taper contour.
• Ships with the M4 barrel extension properly installed.
• Weighs about 2.05 pounds.

Frequently Asked Questions

Does this barrel come with the extension installed? Yes, it ships with the M4 barrel extension properly installed.

What gas system length does this barrel use? A midlength gas system, suited to the 16.1-inch barrel length.

Buy the CMMG 16.1in 5.56 Midlength Barrel Sub-Assembly, Medium Taper

A pre-installed extension and a midlength gas system save builders a step on the way to a smooth-shooting 5.56 upper. Order it from our Lubbock, Texas gun shop for fast, insured shipping.