A good hunting gun is one that will not destroy the animal you are trying to shoot. You want the bullet to kill the animal but you do not want it to tear it apart which would make eating it nearly impossible. The best type of gun that can be used for hunting is an old, yet classic gun that is still my favorite to go hunting with and that is the mosin nagant rifle. It is very high powered and it gets the job done plain and simple. I personally like to add a nice mosin nagant scope mount to my rifle for the best accuracy possible.
The next thing I would like to discuss is the type of ammo, don't use ammo that is not strong enough to kill the animal. That is bad for both the animal and you! I would suggest using 7.62x54R ammunition for hunting for the best results.
A bad hunting gun is going to either tear the animal to shreds or will not be strong enough to kill an animal at long range. Either one is not good. I hear a lot of new gun users ask if they can use their AR15 to hunt, the answer is no!! Even though an AR-15 with an upper receiver is cool or you have a brand new buttstock for your AR you cannot use it to kill any animals. Those types of guns are used for personal use only. So stay away from them when hunting please, thanks.