dig4gold, You wouldn't happen to own a muzzleloader would you? That would solve your problem. If you don't, then I would suggest the 20 gauge as well. My little sister has hunted with a 20 gauge 870 with a slug barrel on it for quite a few years. And the deer we have around here are pretty large bodied and she has dropped them out to 140 yards or so. The past couple of years she has caught the muzzleloader bug so her 870 has been collecting dust. But since she has a slug barrel on it, she has been using saboted slugs. You will be using full bore diameter slugs in that smooth bore 20 so you will have a bit more grain weight to work with. Brenneke slugs should shoot well in it out to around 75 yards with that mod choke.