San Tan Tactical in Fort Worth, Texas, has expanded its 1836 Series with the Ironclad barrel lineup in four configurations for 5.56 NATO and 6mm ARC. The lineup includes 11.5-inch and 16-inch 5.56 NATO barrels and 12.5-inch and 18-inch 6mm ARC barrels, each finished in Black Nitride QPQ and fitted with a gas system sized to the length.

The 6mm ARC barrels use a 1:7.5 twist and 5R rifling; the shorter one has a mid-length gas system and a fluted 4150 steel body, and the longer one a rifle-length system. Production includes honed chambers, polished feed ramps, dimpled 0.750-inch gas-block journals, NTF-coated extensions, complete quality checks, and magnetic particle inspection. The barrels will be sold by San Tan Tactical and its dealers, with more 1836 Series products expected later.