The latest IMR Legendary Powder, IMR 8133, is an Enduron Technology powder. It was designed to provide optimum performance in the large overbored cartridges like the 300 Remington Ultra Magnum, 6.5mm-300 Weatherby Magnum, 28 Nosler and a host of other fine magnum cartridges. It provides excellent loading density, copper fouling eliminator, insensitivity to extreme temperature changes and is environmentally friendly. It is, without equal, the consummate big game cartridge propellant.
“IMR 8133 is designed specifically for magnum calibers, such as .300 Remington Ultra Magnum, 28 Nosler, or the .264 Winchester Magnum, among many others. This new powder has the slowest burn rate among the Enduron powders and compares in burn rate to Hodgdon Retumbo.”