I know that.... But currently only mags specifically designed to meet the 10 round limit have internal blocks in them. Hell, I can take a Wilson combat mag and with some sheet metal magic and a new spring, convert it to hold 20 rounds. Not sure how well it will work, but this basically would mean without any internal block LIKE THE CURRENTLY PRODUCED CA 10 ROUND MAGS would be illegal. Not just Glock and AR mags.