Winchester StaBALL HD is a temperature-insensitive, double-base, BALL Powder, stable in extreme-hot or -cold conditions. This slow-burning magnum powder provides optimal loading density in large capacity magnum cartridges appropriate for the burn speed, which is ideal for 6.5 PRC, 7MM Remington Mag, 300 PRC and many more. Typical of a BALL powder, precise metering contributes to improved velocity and lower standard deviations, ingredients that are paramount to match grade accuracy!