I don't know about using a 200 gr bullet in a 357. Depending on your cylinder length, you may be limited to that length for your OAL. Because of the length of the 200, you will run out of case capacity for its use. I guesstimate that you'll only get under 1000 f/s or so if you're lucky. I would suggest that you think about using a 180 gr bullet instead. You'll probably get better than 1100 f/s with that load in your 6" barrel. Since I use mainly 44 Mag or bigger, I just use the biggest bore I can control if I needed something for penetration. The only revolver that has gotten phenomenal velocities with a 200 grainer has been a Freedom Arms Single Action. They get the velocities because of the tight tolerances built into the revolver. I've never heard of any other revolver that will give the velocities needed except for tight chambered custom 5 shot revolvers.