I had to modify a 10 round AICS to make 22-250 work, and I can only reliably run 9 rounds in it. Had to cut the rear portion of the follower a little deeper. In a unmodified mag once you get the mag full the rounds are pointing down too much and they run into the feed ramp. 5 round mags work fine unaltered. Im told that Alpha makes something that works pretty well with 22-250, not sure if its anything different than their 308 mag, or if it just happens to work better.