Converts the Cavalry Arms and GWACS MKII plastic receiver to accept Greasegun 45ACP magazines. Locks into receiver when upper is fully closed and it is impossible for it to fall out even if magazine button is accidentally pressed. No modification to magazines necessary.
SUB CALIBER BUFFER is required (sold seperately)
FOR OLYMPIC 45ACP UPPER RECEIVERS ONLY
WILL NOT WORK WITH STANDARD ALUMINUM LOWER RECEIVERS