I have a friend that lives on a bit of property with several large bucks on it. He invited me out to try and get one, but the property isn't THAT big and I would have to use a shotgun. Never hunted deer with a shotgun before, so what do I look for in loads? Could I just get away with using my duck gun with a rifled slug? What is the effective range with something like this? Appreciate any help.

You should be good out to 75-100 yards with a rifled slug, less with 00Buckshot if it is legal.

50-60 yards is probably the max shooting with a vent rib barrel or just a bead up front.

I've taken two deer and two elk with a shotgun, but three were with a rifled slug barrel. Don't expect pinpoint accuracy without sights and rifling, try for 9" at 50 yards and if you can do that, WOOHOO! Try the regular 1 oz. rifled slugs if you are shooting from a smoothbore. If it has sights and a rifled barrel, I like the Federal 1 oz. copper sabot rounds.

Longest shot I made on an animal with a rifled slug barrel with open sights is 70 yards. Longest smoothbore shot was 60 yards.

If it is in a firearms restriction zone, you should also be able to use a muzzle loader, even during modern season. This is probably a better option, unless all you have is a scatter gun.