My 30-378 did the same thing every time. factory or hand loads. I brought it to two gun smiths, the last being Bob hart, and after putting a better brake on it and lapping the barrel, truing the action, trigger work, cryoing(spelling?) the barrel, and bedding the action securely, the rifle began to shoot properly as I consider it. It now will shoot 5/8 all day. probably the bedding and cryo treatment had the most to do with it? In my humble opinion the weatherby rifle is not worth the money, only custom for me now. Just ask any of the reputable gun smiths on the site and they will probably give you a list a mile long why they don't like them. Sorry weatherby guys, but this comes from someone who used to love weatherby's. That is until I tried something else! Don't get me wrong I still use, and have my longest kill with a weatherby, I just think the gun should not have required all that work when it cost $1900 when I bought it! No one can deny that most factory rem's can run with any factory weatherby for half the cost. Still, if you have the gun I guess you have to make it work like I did. take it to a reliable gunsmith and let the man do his thing!
you cant dump'em if you don't pull the trigger!