Just got my PM9 and had previously ordered both the A&G grip extender for the 7-round mag, and the Pearce grip extension for the 6-rounder. The Pearce catches the skin on my pinky, and the A&G, well, I won't be carrying with the extended mag anyway. So....I used the Pearce grip bottom and slid the base-plate part from the A&G over it, the result is a black-bottom 6-round mag. Still a bit of a gap as you can see but at least its not bare metal anymore. Haven't shot with it yet, hopefully it will be comfortable enough to keep it this way.
Thoughts?
Thoughts?
But I am not sure if that extra quarter of an inch has actually gained you any extra little finger gripping surface. 
