The Mark II was the most common variant, with two million units produced. It was a much rougher weapon than the Mk I. The flash eliminator and the folding handle (the grip) of the Mk I were eliminated. A removable barrel was now provided which projected 3 inches (76 mm) beyond the barrel sleeve. Also, a special catch allowed the magazine to be slid partly out of the magazine housing and the housing rotated 90 degrees counter-clockwise (from the operator's perspective), together covering the ejection opening and allowing the weapon and magazine both to lie flat on its side.