Different caliber but when I started loading for my 2.75" 69 I was shooting slow (750fps) 44 specials and was not impressed with its accuracy. Granted, the groups were not 12"! As soon as I started steeping up the FPS the accuracy got better and better.
With a 240gr. plated bullet around 1000fps and up seems to be the sweet spot. A hard cast 200gr. SWC might shoot like a laser at 750fps. Bench rest as many bullet weights and velocities as you can before calling S&W.