An embodiment of a hand guard for a firearm, such as a rifle, includes an elongated tubular housing comprising an upper part, a lower part, opposite open ends, and a lumen configured to receive an intermediate portion of a barrel of a firearm longitudinally therein. An expansion collar is disposed at one end of the housing. The expansion collar has an expansion mechanism configured to adjustably compress the expansion collar and the lower part of the housing longitudinally between a pair of surfaces respectively disposed at opposite ends of the intermediate portion of the barrel.