In one example, a method of aligning a firearm sound suppressor includes inserting a front portion of a body of an adapter into a socket of the firearm sound suppressor. The method also includes sliding a tab of the adapter into a slot disposed in an interior surface of the socket to rotationally align the firearm sound suppressor relative to a firearm. The method also includes contacting a plug of the adapter against the interior surface in a complimentary engagement. The plug is provided by a frusto-conical external surface of a rear portion of the body. The tab extends from the plug. Other embodiments are also contemplated.