Don't do it!! The chances of an accident is too high.
If you want to shoot 357 pressures use 357 cases. If you lose track of those hot loads and they get into a 38 you could ruin the 38 and your day, week and month while you recover from the gun coming apart in your hand. Or worse yet someone else shooting the hot loads or some bystander that gets a piece of metal driven into them by the cylinder that came apart.