"Big if true" https://shieldarms.com/glock-43x-48-15-round-mag I have no affiliation with Shield Arms, but I've seen a few threads on this around the web & thought it would make for an interesting conversation here. Supposedly they'll be out this summer. If they make it out before the Iowa caucuses, I'll be impressed. If they function reliably, even moreso. Apparently there's a lot of wasted space in the polymer G43x/G48 10 round mags. Metal mags make this possible. CZ 75 Compact mags apparently also work with modifications for the mag catch.