I don't know of any current S&W J frames that can't eat +P all day long.. I thought they had stretched the frame .1 inch and the current models use the .357 Mag cylinder??
As an owner if a 342, Lite the older 10oz version of the current 642/442 J frames,, the limit is the pain your hands can handle..
I use anything for the range. It's a 25ft last choice defense. So I don't dwell on ballistics..
Having said that.. When I do carry the 342, I carry Speer Gold Dot "SHORT BARREL". It's +P, but also tuned to 2-3 inch barrels, without pressure problems.
AND I carry two speed sticks, the 8rd version.
My $00.00002