Given the number of people who are intimidated by the recoil and blast of a .308 or a .30/06, the suggestion of a 12 ga for a novice's bear gun does not seem entirely appropriate, and managed recoil ammo has no place in a big game shotgun. If someone seriously asks me what rifle to use on a bear hunt, because they really don't know, I would probably suggest a 6.5X55 or a .260 Remington, loaded with 140 - 160 gr bullets at the lower of the power spectrum, to the .30/06 with 165-180 gr bullets at the upper end. Probably a .30/30 lever gun is a good compromise. If folks are going afield with no shooting experience, there's not much that will help them, laser pointers not withstanding. Big game hunting without some basic marksmanship experience is akin to parachuting without going to jump school. Aside from being unsafe to all concerned, its not fair to the game. I don't understand why anyone would do such a thing, or for that matter, would want to.
Rereading post #1, the OP suggests he already has an SKS and a 12 bore, but we don't know what shooting experience he has. We know he doesn't handload because he talked about purchasing a case of ammo, so loading 7.62X39 ammo that is appropriate for big game probably won't happen. We can assume the 12 ga is equipped with neither rifle sights nor optics, and we can further assume that he has not attempted to hit a realistic sized target with slugs with his bead sighted shotgun or determined his group size or trajectory at a variety of ranges. Perhaps the best advice is that he holds off bear hunting until an appropriate big game rifle can be purchased, and until such time that he has managed to develop some level of competence with it.