It really depends on the combo, but 50-100 fps is to be expected. I've seen that spread with Imr, H, and RL. I don't burn much ball powder, but that can sometimes be a bit worse.What differences do you notice in velocities between cold weather shooting and warm weather shooting
Lefty, i can try to get some of that info on some retumbo in a 338 Lapua and h4831 in a 25-06.also remember that not all H powders are the same. Some of the older ones like H 4895 even though "extreme" will vary quite a bit; I've seen 100 fps with H 4985 between cold and hot. Some of the newer ones are better I'm sure, but I use rl more so I really don't have good data on what North Dakota does to H powders.