only lot to lot variation I have saw that was truly mind blowing was using RE22, I realize its a double based powder, and they are more temp. sensitive than single based powders, but under the same conditions, using the same charge and components I have witnessed 150 fps variation just changing lots. I no longer use the RE line of powders. now my disclaimer, I shoot long range, practice regularly to 1100 yards, I can adjust the load for various temps, but I can't rework my load every lot of powder....barrels get expensive!
RR