"If you put it in the boiler room, they will die." (Has to be said with a cheesy Swedish accent.) But seriously, you aren't going to find a much better rifle for what you are hunting, as long as you know your range limitations. As for diameter, the current Marlin barrels are running pretty close to spec so I'd try .459" and it'll probably work. If not, slug the bore to find out what your rifle needs.