Picked up at a gun show a while ago some .458 250 gr lead bullets for the 45/70.... they where cheap, and I figured they could be cheap plinking rounds. my problem is, I can't find any load data for a 250 gr lead slug. I'm almost thinking these are for something else? They all measure out at 0.458, and weight is all mostly right at 250. Gr. New to the 45-70, all I've ever reloaded for was 44 mag. Any help?