I've got the Bersa model 380 with nothing but the 9 round mags and have the same situation. Vaguely I remember that being a concern years ago when I first bought it and started carrying it as my EDC. When I read your post, I actually had to draw it from my holster to check it because it has become a non issue for me. I just reach over with the fresh mag in the left hand, and hit the mag release with my left thumb, let the empty mag fall and reload the new mag.