I don't actually believe that the two lugs and slotted action provide a terribly strong lockup. Lock the thing in a rest, slide a rod down the barrel, give the rod a sharp tap. Watch the action twitch like a frightened squirrel.
I don't think that the thing will kaboom, but imo, the fact is that the thing isn't a terribly strong action, and it may stretch and warp after a long run of rounds that are past maximum.
The revolver is pretty simple and strong as a rock. The cylinder does nothing but hold the round in place against a monolithic breech block, and contain the discharging powder. The rossi barrel shouldn't blow out, it's heavy enough to support the round. It would take a heavy, heavy round to blow the action out. the dual bars can take the pressures and energy that a .357 can generate. excessively high loads still and probably will eventually blow primers, stretch the action parts, put unnatural wear on load bearing parts.
But in any case, IIRC, the strongest loads possible for a .357 are with 296, and that is almost a crushed load. Trying to pump fullest possible velocities out of a faster burning powder is futile and kind of dangerous in any situation. So, my point is, that the fastest possible round in a .357 may be already possible with a 296/2400 load?
