My hunting partner used the XP3 2 years ago on a mule deer doe. At about 300 yards he shot the doe broadside and it left an exit wound that you could almost put a basketball in. It was seriously the largest exit wound I have ever seen.
We hunt both deer and elk at the same time, and I think it would be great for elk, but may be a little overkill for deer. In any event it will work without a doubt.