Keep in mind the size and weight of the gun. Do you really want to fire .357 ammo in it?

The best bet is probably the Speer Short Barrel 135 grain medium .357 load. It's optimized for gun like yours.

When the J-frame .357's came out n the 1990's, an acquaintance at S&W told me that he fired a cylinderful of Magnum ammo in one, for familiarization. Said that the first shot wasn't too bad, but by the time he'd fired all five, he thought, "Thank God, that's over!"

I found that a snub M-19 with full loads is about as small a .357 as I can use effectively. Haven't tried .357's in the SP-101 yet, though. I bet that you'll prefer .38 Plus P ammo. Especially indoors!!

That's particularly true if you have to ask which .357 ammo is best. That suggests that you haven't fired one of these guns yet with full loads. You may have a bit of a shock coming...

If someone has a larger one, a K-frame with 2.5 or three-inch barrel, the 140-145 grain loads are very efficient, giving about 1200 FPS from a three-incher. And they probably penetrate well enough to take on a cougar, maybe a black bear or alligator. (Humans are easier to kill, on the whole.)

One gun editor killed alligtors handily with 125 grain Magnum loads in a snub M-66. I'd feel better with a heavier bullet. I've read that poachers kill them with .22's at night, jacklighting them. A defensive scenario is different.

T-Star