That sounds like a small amount of a fast burning powder for that cartridge. I can' t remember off the top of my head what I load in my 300 Win and Wby Mags but it' s RL22 and more than 62 grains. I think the powder change will help things a great deal. I use RL22 in 3 different magnums and it' s the best for all 3. Try it. Usually the max load in the manual is the best for my rifles but it might not be for yours. Rememeber to work your way up from the minimum when you try a new load and watch for pressure signs.