I tried a giessle and dd mag catch on mft, magpul 20 and 30s, e-lander and CPD. All catch and release with upper on and off and bcg in and out. The only mag problem I've encounter is the mft feed lips being to thick and cause the bolt to drag and not fully go into battery while shooting. Problem doesnt exist with the other 3 mags. All drop free and no issues seating when loaded or empty.