If this is a shotgun... it is a smoothbore. That means if you have no choke at all, you can shoot a roundball, but the accuracy will not be long range by any means. Also if this is a double barrel I read it is not recommend because it can stress the center rib.
If you want to hunt deer get a rifle. Save the shotgun for turkey.
"Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, a total wreck, screaming Yahoo, with a big smile on your face."