Comparative Powder Burning Rates

Comparative Powder Burning Rates: "Temperature Effects on Powder
Effect Of Temperature On Various Powders
(0F) (70F) (125F) Changes
Powder Pressure
(kpsi) Velocity
(f/s) Pressure
(kpsi) Velocity
(f/s) Pressure
(kpsi) Velocity
(f/s) D P
Cold D V
Cold D P
Hot D V
Hot
Accurate 2520 50.5 2781 49.9 2805 52.6 2844 600 -24 2700 39
IMR 4064 51.3 2651 51.1 2686 49.7 2697 200 -35 -1400 11
Reloader 15 48.7 2665 50.3 2715 47.3 2705 -2100 -50 -3000 -10
Win 748 47.3 2655 50.2 2724 51.1 2769 -2900 -69 900 45
Varget 51.2 2778 51.1 2771 51.5 2779 100 7 -440 8
Vit N140 47.5 2629 49.6 2665 51.0 2679 -2100 -36 1400 14
Vit N555 48.8 2778 50.1 2808 51.5 2834 -1300 -30 1400 26

Data based upon the 308 Win. cartridge using all the same lot number Winchester cases, Winchester Large Rifle Primers and Sierra 168 gr. BTHP Match bullets. Note that many ball powders can exhibit unexpected extreme changes in pressure below 35 degrees F and above 105 degrees F, rising pressures 10,000 psi or more at elevated temperatures. Be careful at the temperature extremes! In addition do not use ball powders at very low load densities.

Data courtesy of Varget."