The ProMag PM237 is a magazine block adapter which easily installs in a standard Ar-15 lower receiver to allow the use of 9mm Colt SMG pattern magazines. This is the key component that you must have in order to make your AR-15 9mm conversion work. The block is constructed of high strength polymer with steel hardware, roller, ejector, and bolt stop.
Specifications and Features:
Converts from standard AR-15 lower to 9mm AR-15 lower
Allows for use of 9mm Colt SMG magazines
Made from high strength polymer, with steel hardware
Standard Pattern AR-15 lower receivers