 Sterling later produced black-enameled steel magazines in 20- 30- and 40-round capacities that did have cutouts and were able to feed from an AR-15.However, the AR-18/AR-180 was never capable of using the Colt AR-15/M16's stock 20- or 30-round STANAG magazines.Gunsmiths have been able to convert AR-15/M16 magazines to feed in the AR-18, but they have to have modified followers or it will put strain on the bolt catch.