Win 748 is a great powder for the .300 Savage in a 99 I used 42gr /150gr .....41gr/165gr .......and 40gr/180gr with magnum primers used in all being ball powder and for me -40 temp The SST will require backing off a couple grains and working up your load. Winchester brass BTW All shot under an inch at 100 yards mostly 1/2" after coffee.Use at own risk obviously.Harold