I have a Mossberg bolt action 20ga. it has a full choke on it that looks to be original. I'm currently hunting with it because I haven't purchased a rifle yet. Question #1 is What rounds or "shots" are best for deer hunting? #2 Is it or is it not possible to shoot slugs thru this shotgun? #3 If so then what slugs are prefered for this type of shot gun? Thanks guys!