The CMMG 16-inch .350 Legend Barrel Sub-Assembly (brand part no. 35D5F0A) is built for shooters assembling a custom Mk4-pattern AR-15 upper in the straight-wall .350 Legend chambering. CMMG machines the barrel from 4140 chrome moly steel in a medium-taper contour, finishes it with a salt bath nitride coating for corrosion resistance, and ships it with the M4 barrel extension already installed and properly headspaced, so builders can skip a separate gunsmithing step. The carbine-length gas system uses a 0.750-inch gas block journal, keeping it compatible with common low-profile gas blocks. For builders who want a ready-to-install .350 Legend barrel without a trip to a gunsmith, this AR15 barrel saves a step in the build.

Key Specifications

• Chambered in .350 Legend, a straight-wall cartridge popular for hunting in shotgun-only states.
• Barrel length measures 16.1 inches, legal for a standard rifle-configured lower.
• Rifling twist is 1:16, matched to typical .350 Legend bullet weights.
• Uses a medium-taper contour for a balance of weight and heat dissipation.
• Machined from 4140 chrome moly steel for strength and durability.
• Finished with a salt bath nitride (SBN) coating for corrosion resistance.
• The muzzle is threaded 1/2-28, the same thread pitch used on 9mm-bore barrels.
• Uses a carbine-length gas system with a 0.750-inch gas block journal.
• Ships with the M4 barrel extension pre-installed and properly headspaced.
• Weighs about 1 pound 9 ounces, light for a 16-inch barrel.

Frequently Asked Questions

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

What gas block does this barrel need? A 0.750-inch gas block matched to the carbine-length gas system.

Is 16.1 inches long enough for a standard rifle? Yes, it clears the federal 16-inch minimum for a rifle-configured lower without NFA registration.

Buy the CMMG 16in .350 Legend Barrel Sub-Assembly, Medium Taper

A headspaced, ready-to-install barrel sub-assembly lets builders finish a .350 Legend upper without a separate trip to the gunsmith. Order it from our Lubbock, Texas gun shop for fast, insured shipping.