Originally Posted by samurairabbi
A possible point of confusion on 29/30 mags:
There is a NINE-round G30 45acp mag, that matches ALL external dimensions of the 10-round G29 mag. Aftermarket baseplates meant for one will work with the other. In particular, the Pearce PG29 plus-zero mag extension WILL work with the 9-round G30 mag. When I was carrying a 30, those 9-round mags with the Pearce PG29 extenstions were useful for concealed carry.
The TEN-round G30 mag is built differently at the BOTTOM of the mag, to accomodate the tenth round. Aftermarket baseplates intended for this mag are NOT compatible with the G29 mag.
Thank you rabbi, when I was reading the OP this is exactly what I intended to post as an answer.
So, not that someone like me really even has to say this, but the rabbi is correct!