Greek54

Hi. I am an intermittent post at best. However, once in a while I have a question, so here goes. I have a Weatherby Mark 5, Ultralite in 7MM Remington Mag. I cannot get it to shoot better than about 2&1/2 inch groups with a anything at 160 grains or above. It is a 1 in 10 twist would like to get some suggestions. Should I sell it, try to have it accirized or re-barreled? Thanks for the help.