Tons of guys have had single shot smooth bore guns that they shot slugs out of during deer seasons for years and years. Not a thing in the world new about that scenario!

The largest "weak-link" is the sights. Maybe a notch in the back and a BB up front. But guys have killed plenty of deer with the same setups.

Effective range (consistently and reliably hitting the target) varies. 50 or maybe even 75 yards may not be out of the question.

Personally I'd try some basic Foster-style (pumpkin ball) slugs from Brenneke, Winchester and Federal. See what seems to shoot best for you.

And I have to say it but DO NOT USE REMINGTON SLUGS. I have just seen too many failure to fires with Remington and it seems their brass is cupped causing the primer to be too far away from the firing pin. From here on out I trash Remington. It has been an ongoing problem for WAY TOO LONG.