IMR 4064 is temp sensitive. All powders are, some just more than others. I can say that I’ve shot more 4064 than any other powder I’ve used. It was my main powder I used in 3 of my prairie dog rifles, for more than a decade. I burned out 6 barrels and shot those rifles from 30° up to 105°. It’s a great powder in my book.


JTD