[QUOTE=Saudade;139507003]If your M&P is the fullsize (4.25 inch barrel) then you need the fullsize mags. Some places may not specify since 17 round mags are full size. There are reduced capacity mags (15 and 10 round) for restricted states but those just about always specify. You slide should read M&P 9 up by the front sight.

The M&P9 Compact says M&P 9c up by the sight. These too generally specify Compact. Full size mags will fit the compact, just stick out a bit more. Compact mags will not fit the full size.

Great, I will check this out carefully before I order.
Thanks, CMA