Armscor Magazine, Rock Island, 10MM, 8 Rounds, Fits 1911, Blued Finish 10-777 The Rock Island Armory Full Sized Magazine is a standard factory replacement magazine. This magazine is for Full and Mid sized 1911 models chambered in 10mm and holds 8 rounds of ammunition. It is made of steel and is made to Armscor/Rock Island Armory specifications and tolerances" using the same manufacturing and materials as the original equipment magazines" ensuring perfect fit and operation.