The peak felt recoil and the length of that recoil force may well be different depending on the burning rate of powders. However, I am guessing that the difference is very small. Another point to consider is that the burning rate difference in acceptable loads for a certain velocity and shot load is very narrow. A 1 ounce load at 1150 fps is a great load in all weather with Red Dot. With the next vintage Alliant powder up the rate chart, Green Dot, this load is a summer load at best. We don't have all that much choice in burning rates in the light loads we like so much. In heavier loads, we are already using very slow powders, so what is this discussion really about, real life or laboratory results?