Mec-Gar makes a high quality mag for the Browning which holds 15 rounds and doesn’t protrude from the grip. They also make a 20 round one which does stick out a bit.
Also the Argentine military Brownings come with 15 round mags standard. I am not sure why FN still used 13 round mags in their Hi-Powers but they do.
to quote Tevia... “Tradition”