You can do the job, and do it well, with anything rom a 7mm-08, all the way up to the 7mm mag. But Brutal Attack has already hit on what I was going to suggest. Look at the available calibers are for that model of gun, and see if it has any of the new short magnums available. A 25wssm, .270 short mag. , 7mm short mag. Those are very effective, and can handle a lot of game.

Just a thought of other options, that might work better for you. Take a look at their specs and compare them to the standard rounds. You will see some difference.