[m&p45acp10+1]

I have hear of a few guys that load the real heavy bullets for .357 mag in .38 spcl cases(190 grain). Though due to the longer bullet they will not chamber in a .38 spcl revolver. I would recoemend using .357 brass anyway. While it may be safe in your gun, think of what would happen if you dropped a couple of rounds at the range not knowing it. Someone finds it later on, and loads it into an old top break or weaker .38 spcl.