Hodgdon Powder offers the largest selection of quality smokeless propellants for any reloading application. Hodgdon RETUMBO is a magnum powder was designed expressly for the really large overbored cartridges such as the 7mm Remington Ultra Magnum, 300 Remington Ultra Magnum, 30-378 Weatherby Magnum, etc. RETUMBO adds 40-100 fps more velocity to these cartridges when compared to other normal magnum powders. In addition, it is an Extreme Powder, making it perfect for big game hunting under all types of conditions. Warning About Smokeless Powder: Do not exceed the loads displayed in the reloaders guide. Never mix any two powders regardless of type, brand, or source. Never substitute any smokeless powder for Black Powder or any Black Powder substitute.