The other day my brother called me up to ask if it was legal to hunt with the AR-15 that he had recently received as a gift. I explained to him that the short answer was:
It is legal to hunt with an AR-15 as long as you are following the caliber requirements and magazine limits required by your state. Many states do not allow you to hunt big game with a .223 caliber round, but this can easily be remedied by swapping the upper receiver to a larger caliber.
When reviewing your regulations make sure to verify that they allow semi automatic rifles, what calibers they require and if they have any magazine limitations. For example some states do not allow a magazine capacity larger than five rounds.
The AR’s Ability to be Easily Modified makes it an Excellent Hunting Rifle
The best thing about hunting with an AR is that you can keep several upper receivers that are chambered in different calibers. This will allow you to have one chambered in .223 for hunting small game such as rabbits, goats and coyotes. At the same time you can carry an additional upper receiver chambered to fire .30 Remington or .300 Blackout cartridges for taking down deer, and black bears.
Due to the barrel and upper receiver essentially being one nearly solid part once put together you can also leave scopes attached to the upper receivers. This will allow you to have several scope variations depending on the hunting conditions.
State regulations for hunting with an AR-15
Due to the vast differences in state laws, it would be nearly impossible for me to list them all here. However, I have gathered links to each of the states and hopefully you can find the information you need there.