Best slugs to use plain old Brenneke Classic, Winchester or Remington in any smooth bore 12 ga. with 18" barrel and sights preferably....I left out Federal slugs because of bad experiences with the brass near the base cracking on the rim when firing shooting out gasses in your face in many guns especially if your left handed shooting a right hand gun like me....
Using these slugs will put a 70 caliber hole braking bones and letting out a lot of blood and knocking the fight out of a bear....for many years I used a Remington 870 with a 18" smooth bore and sights about the last 15 years a Benilli M1 with pistol grip 18" barrel trillium sights and shell extension tube to hold 7 shells....
Running baits using a shotgun even tho its better if you get into a fight they are a pain having to load and unload at every bait even carrying with two buckets and using a sling over your shoulder....the only reasons a handgun is preferred is with a CPL just keep it loaded and under your jacket when riding in a vehicle or ATV and it very easy to get to if you need it....but just don't have the stopping power of a shotgun slug....
I always when picking up a hunter at a bait site carry a shotgun....
For many years I hunted in Canada and a handgun was out of the question shotgun with slug was the only choice....