They work very for deer, even using the .223. I shoot the Rem 55gr softpoint.
Proof is in the pics. Postmortum inspection showed a large hole through both lungs. The deer ran about 30 yds before piling up.
I love seeing those pictures. My daughter is still not big enough to shoot my rifles but she can shoot my AR VERY well. I really don't want to spend the money to buy her a youth rifle for here to use a couple of years. After the season last year we went out and found a couple of 5 round mags and she is practicing for the upcoming fall season.