Trapper 458.
First off i use a larger case than your 300 wm in which im loading 97 gr of retumbo. And i (prefer) using 190 gr
bullets in that gun for long range hunting. Weve killed deer beyond 1100 yds with it with those bullets very affectivly.
A 190 gr bullet at about 3400 fps does an awsome job. If your gun shoots the 190s well thats what id be using and dont
worry about what others say or think. Much of the advice about what (you) should do will be coming from people who never
killed an animal long range. Some might even argue the advantage of a smaller cartridge. Velocity will trump a higher B C
to a certain point. By the time youve reached that point with your 300 wm its over for that gun anyway for hunting.
Im using 190 smks in my gun and they perform very well on animals. You might even try 200 smks in your gun.
For many years i used 200 smks in a 36" barreled 30x378 with a velocity of 3500+ fps. If your getting good groups at 300 yds be happy.
So where in eastern MT are you, as i have rancher friends west of Volborg.