Do you have any of these powders sir? IMR or H4198, Accurate 2015, either of the 4895 powders? The 60% rule on 4895 works in the 458WM just fine and the others I listed are easy to light and highly probable to be able to develop the light load you want in only short experiments over a Chronograph. I personally use AA 2015 in my cast loads for about 1750 FPS with 485 grain bullet using 51 grains. I would guess that somewhere between 60-65 grains would launch a 350 at your 1950 fps target speed. Sir Ron will chime it with lots of help at his first opportunity I am sure. Best regards, F01
