Was it Elmer Keith who once said, "the 375 H&H makes a nice little deer rifle"...so you would be moving it to medium bore and 500 Jeff to the biggie!500 Jeffery
If you want to put a suppressor on it, I would stay at .30 caliber or smaller just because the can gets so big and heavy over that. So why not go back to the venerable 30-06? Or a 308 if you wish but the 30-06 is so much more flexible and so close to a magnum.