My little sister is going to deer hunt with a little 223 that we have killed deer with and have also loaned it out to friends for their kids to use and they have all killed deer and antelope with it. I have no problem with someone using a 223 for deer sized game but they need to know proper shot placement and practice practice practice. Ive also used my 22-250 for deer and antelope and i plan on using it next year.