Well that was interesting
Did some more shooting with the 342. I noticed that the 158gr +P LSWCHP have less recoil than my reloads; I will address this (I think I know why), but for now its a reassuring sign. While the +Ps were still not pleasant to shoot, they were a lot closer, and I'd consider keeping the gun now. Especially if I find a standard pressure load that is effective.
Crimp jump did not cause the cylinder to lock up (though I only shot a few cylinders full). However, the bullets did get pulled slightly. Picture attached.