@jtcarm - I got 1080 fps using a 170-grain SWC over six grains of Unique in .38 Special cases from my 4" 681. You could back that off somewhat and get 1000 fps from the Blackhawk with less recoil and unburnt powder. I personally wouldn't use slower-burning powder for that unless the improved accuracy merited shoveling all the unburnt powder out of the gun.