OH WOW!

If your (and our) identification is correct, you have found one of the truly rare and most difficult to obtain of the M&P variants, one some of us had never heard of and most of us have never seen! Not only is it a rare one to own, but it should be lots of fun to shoot as well!

As for your ammo question; if we are correct and it is indeed built on a M&P frame, you have the option of shooting the 32 S&W Long for which it is actually chambered, the older, shorter 32 S&W (sometimes called "32 S&W Short") and even the semi-rimmed 32 ACP, with safety. As late as that serial number shows it to be, the heat treating is such that it can withstand pressures that any of these generate and still have a nice margin of safety.

Congratulations on a great find, and by all means please post pictures, we love pictures around here!

Regards,
Froggie