Mike, what would be the difference between ten grains of sand and ten grains of inert coating on the grains of a slow burning powder? I think we all know that not every grain of weight in gunpowder is gas producing, or at least I thought that everyone knew that. How does the equation know the difference between actual gunpowder and inert filler or coating? Jim, no, I'm not neccesarily hardheaded, I just don't believe it is a legitimate equation when used to compute recoil. Jim Legg, I guess I am offending your idea of "discussion", so I will write less and read more.