For best results with Trail Boss, seat bullet base 1/16"above powder. NEVER compress this powder, it will do bazaar things! I use it for lower velocity pistol and rifle rounds. I have a 38-55 Win. 20 shot group in less than a dime at 100 yards, with iron sights (Globe and Tang) from my modern made 1885 High Wall. Trail Boss meters well out of most powder measures (avoid the plastic ones because of static charge, that will make charge erratic). Have Fun! Ivan