I thought that any of the lower powered .32 caliber rimmed cartridges could be shot out of the .327 Mag revolvers, all the way back to the old .32 S&W.We have a M&P R8, but it only comes in a 5" 357 Magnum for about a grand (357 Mag also chambers 38 Special, for lower recoil shooting). I've never seen 327 Magnum ammo on any LGS shelf, and the 327 Mag only uses one type of ammo (no lower recoil/lower price ammo compatibility)