Oh yeah all the time. I bring my 12 gage and rifle with me while I hunt black bear. I keep the shogun by me in the vehicle (only cause lately I have wanted to get one with a slug) but most the time I just use my lever action 45-70 marlin. You can easily go after black bears with a 12 gage slug, as for deer OH YES most certainly. As for the effectiveness range I would consider 150 yards max with a slug gun for deer, and 100 yards for a black bear (foster slugs). If your thinking brown/griz stick with a guide gun lol I wouldn’t go after those with a shotgun. Now that all depends too if your using foster slugs, or sabbot slugs, or trophy slugs. Cause apparently the new slug guns work wonders with sabbot slugs at up to 250-300 yards. You have to remember these are pretty much .50cal chunk of lead. Also foster are ment to be used in FULLY rifled barrels, will it harm your mc,ic, most likely after pr-longed use. What I’m curious about is why slug gun, foster slugs in my area cost 20 bucks for a box of 5. 30-30, 308 are more expensive by a dollar or two while providing 15 more cartridges. Are you hunting in a shotgun only zone?