I used a Cooper last year. I hadn't used a muzzy in a long time. I was amazed at the accuracy. It shot great with BH209 and PB's. I would of liked to use sabots but you can't in Colorado. It would shoot MOA with most loads I tried which admittedly wasn't allot since the bullet I wanted to shoot, shot so well. I will be hunting muzzy a lot more now after seeing how accurate they can be. Definitely didn't feel very handicapped using a muzzy instead of a rifle.
Just a suggestion... you should look into the .50cal Fury bullets. The .50cal Star Tip is an outstanding bullet on game, shot land riding with a wad, no sabot. Its a better bullet by far and very accurate out to 300yds. Fury has a sizing package, so you can test the force to load in your rifle. Once you determine the correct size, Fury will size them for you, or you can buy a Swinglock die and size them yourself. They will HAMMER what ever you intend to hunt.