I have a Classic Stainless M-70 in .300 Weatherby. The rifle is currently bedded into a McMillan stock, I'm thinking of rebarrling to the 7mm-300 Weatherby. New barrel will match the factory barrel contour, perhaps fluted. As I understand it, the mag box of the M-70 is limited to 3.70. Will this be an issue with 180 Berger VLD? Gunsmith recommendations? Thanks all.