When I worked in Browning's gunsmithing shop I used oak jaws to which I glued 1/2" cork. The oak portion was notched to fit over the screw housing, a folded shop towel covered the vise screw housing and another was folded so as to cover the cork jaws. This arrangement provided a firm grip and I never dented a stock, just remember to change the shop towel frequently so the little bits of debris that tend to accmnulate do not become embedded in the stock.
