Does anyone make reliable hi-cap mags for the High Power....??
I think MecGar used to make a 20 rounder...But I have not seen it lately.

Or does anyone make a base plate extension for the mags (+2 or +3)???
If I could turn my MecGar 15 rounders into 17 or 18 rounders, that would be cool.

Thanks,
-CG

http://www.pearcegrip.com/Products/Browning/PG-BHP9

Thank you sir.  I should have bought a few of the 20 round MecGars when I could have.

The included baseplate inserts did not work at all for me. I got some strip stainless from the hardware store and bent some square U's and filed the ends sharp, while also filing the followers a bit so there would be no interference. The magazines are now 18-rounders, but don't reliably lock the slide. I would pair these, the custom metal inserts, with a Wolff high-power spring. But they do fire reliably as is now.