I used a lot of 4831 and 3031. I came up with a load for my 7mm mag using 4831, i know to slow, and a 160gr bullet running over 2900 per/sec. Looked like a muzzle loader just went off. I guy I know said to me one day lets go shoot. Of course I don't pass on that type invite if I can help it. We go to his range, the one HE gos to, and its got these steel silhouettes out to 500 yards. I plop myself down and get the go ahead to shoot and boom,,, blangggg. He goes did you just hit that 500. yup i did. hold over 24 and squeeze. The thing with slow powders is, it keeps the chamber pressures down and continues to burns as it goes down the barrel. This way, rule of thumb, you gain 25 ft per second per inch up to a point. but true with most barrels lengths.