If you love BDMs, then you know that factory standard-capacity magazines are about as rare as hen's teeth. Even the factory 10-rounders and questionable Triple-K/ProMag hi-caps are drying up.
CDNN has FN HP DA/SA standard capacity magazines, and
after doing some research testing, it seems that these are NOT compatible with the BDM platform.
BDM top, HP DA/SA bottom:
I ordered a few, but won't be able to verify fit and function until I get home. At $40 a pop, I figured it was worth a gamble, considering factory 15-rounders (when you can find them) have been going for over $100 lately.
UPDATE: Unless the magazine catch is slightly dremilled out to match the BDM magazine catch hole, it will not lock in, and the baseplate would have to be "thinned" out in order for the magazine to be able to lock in fully once modified (baseplate thickness prevents the magazine from locking up fully). This is going to be a PITA in order to make them work, but maybe worth it for someone willing to do the work. As it stands, my research was incorrect. Unmodified Browning HP DA/SA mags will not fit or feed with the BDM without the above modifications.
Sorry guys.