IMR 4895 is a tad slower burning than H4895. They are BOTH "stick powders", however, IMR 4895's "sticks" are noticeably longer than H4895. When I was prairie dog hunting, I never found IMR 4895 to be any LESS sensitive to temp changes than most of the "extreme" Hodgdon powders. I know that IMR 4895 will produce HIGH velocities in many cases. In my 22-250 and .220 Swift, it was sizzling! It has always been a VERY accurate powder in all the rifles I have used it in.