Jan 10, 2015 · In your initial quote, "In contrast the M118LR loaded with RE-15 powder will see a 50 fps rise in velocity for a 50 deg rise in temperature.", with a 2640 f/s muzzle velocity, this represents less than 2% change in velocity. From Accurate Powders FAQ's: Most of our powders are not insensitive, and will show some effect at hot and cold temperatures.