I dont want to be bad i want to be the worst
.
.338 winchester magnum would be a good gap filler.
6.5x55 swede would be another good one.
.243 which is one of my favourites.
.257 roberts is anothe good one for that mid range rifle.
.340 Wereatherby for that larger gap filler.
Oh i could keep on being a bad influence.
Good luck with your choice.