I am not suggesting you should hunt with an AR. However, if you did, for some reason, want to hunt with it, a 5 round magazine might be required.
I understand, and I am not being critical. I have several AR’s and I love them. They are great fun, and reasonably accurate. The AR10 could hunt deer though I prefer the Mauser M98 or the Remington.
I never considered buying a 5 round mag for my AR’s. They make 30 round’ers (25’s for the Armalite) and there was simply no reason to buy anything less.