I have 3 hi-cap 13 round 9mm non-leo factory HK USP Compact mags. They do exist. I'm told that they were made in anticipation of the ban before it actually went into effect (though conflicting sources say they are illegal imports) (similarly, I have 5 16 round 9mm Walther P99 mags for which I was told the same story). I've never seen any hi-cap non-leo HK USP Compact mags in .40, though.