the mag catch is too short. You probably already know the position of an AW mag in the chassis is critical- you need to get the mag up further and stay there. It may sound hillbilly as hell, but you can take out the catch, measure the OAL of the part, peen the end out around + .030 (I cant remember exactly how much), then file/grind the end back the part. You will need to smack the mag to get it to catch in the chassis, but the feeding will be good to go with the AW mags. If I remember correctly, doing this will DISABLE the ability to use std center feed AICS mags, the lips will be too high up to allow free passage of the bolt. Either that or make a catch thats longer and needs to be ground and fitted to length