So you're saying if you load 11rds in your mag it will go in OK? It's not uncommon with Hi-cap guns to need a good slap to seat a fully loaded mag when the slide is down. The pressure on the top round to push it down another 1/8" or so to lock it in can be a chore. It will get better as the springs settle in but you may want to download your mags one round till then.