Like i said before a .223 is plenty on deer if you take broadside shots only. A 22-250 is another choice. Ive seen it used with 55gr hollow points blow huge holes in deer, you cant beat that performance.
And again I wouldn't use either. I mean come on, there are reasonssome states have laws that ban such small calibers for deer. "blow huge holes in deer", hell if thats what you want to do, go to your local gun shop and have him order a 50 cal military rifle, build her a custom lead sled type deal and let her have at it.
look at it like this. Those rifles shoot the SAME size bullet you shoot at a squirell. But to each his own.