IMR 4064 Smokeless Powderimr 4064 is easily the most versatile propellant in the IMR line, used for 223 Remington, 22-250 Remington, 220 Swift, 6mm Remington, 243 Winchester Tremendous Brief Magnum, 308 Winchester, 338 Winchester Magnum, as well as the list goes on and on. Versatility with uniformity and precision.This smokeless powder is actually