I have the same gun (bead sight, fixed modified choke). I haven't shot a slug out of it in 10 years. However, my effective range was about 40 yards. Perhaps you can reach out a little further with better ammo that is available these days.

I would buy several boxes of slugs, wear plenty of clothes to pad your shoulder and head to the range. Unfortunately, I don't remember exactly which brand of slug my gun liked, but I do recall it shot 2.75 inch shells better than 3 inch shells.