Re: 243 what grain
80 will work for deer, if it's a well constructed, bonded bullet of some sort. A lot of the lighter loads in 243 are varmint loads, with bullets meant for rapid expansion/fragmentation. I would pick a 100gr load that shoots well, let her shoot it at groundhogs all summer, and she will be confident when she hits the deer woods in the fall. If you're dead set on the 80gr weight range, just make sure you pick a good bullet, and you'll be fine.
I think I'm an alright guy, I think I'm alright