What do you consider "high cap"? Not to be a ####, but it's already illegal for most, if not all, of us to even own standard cap mags. (That and I airsoft, so when somebody said "high cap mag" I think of those wind up 300BBs/mag AR-15 mags.) If you mean 10 round 7.62x39 mags, Wolverine has them in stock, then you could try to add the GSD LAR extenders to make them 10/30 7.62x39 AR-15 mags.