5.56mm
We have them only for target shooting fun.
All the rounds we've fired have been Magtech 158gr. Those were only FMJ until recently when I got some semi-jacketed hollow-point which gave us both _jamming_ problems. Revolvers are not supposed to jam. Ever. I think the cartridge casing of the SJHP is very susceptible to overheating when firing more than 15-20 rounds.
I got some more FMJ and we'll try out a mix of the two types of rounds at an indoor range today. If the SJHP still gives us problems, I'll sell it for whatever I can get, and replace it with some .357 for self-defense purposes.
Yes it is. I dropped a running coyote at 60 yards with a single shot from mine. Yeah I know, lucky shot.