it is all in the bullet selection. you can now buy a .223 in a 75 grain soft point that will lay a deer out like a rug. you said your shots are short a 125 yardsor less. you'll be real surprized how fast the .223 will put a deer down. i would not worry a bit about using the .223. it has alot more power than people think. from what i have seen most people are over gunned. our shots around here are also quite close usually under a 100 yards.alot of times under 50 yards. in our case a30-30 or less is more than you would ever need. i would say if she can shoot the .223 use it. not that this is a good idea but i have seen deer go down with a 22 long rifle.