If the choice is between a muzzleloader or shotgun I would go with the shotgun. With a muzzleloader I have many problems with powder getting wet and consistency when I am hunting in wet or snowy or cold weather and multiple shots is nice.
I don't know how old or big of a guy he is but if he can handle a twelve gauge with 3" partition gold slugs that is the most deadly combination in my opinion.
In a bolt gun or break action the recoil is extremely severe!
In my area most of us have gone to using gas operated auto loaders which take a large portion of the recoil out. Between all my buddies we have owned them all. The extreema and extreema 2 is a disaster, jams every time you try to unload, finicky about cycling different brands of ammo, and is expensive. A few friends bought them and they have never been used a second season. Super black eagles are lightweight and feel nice until you shoot them. They recoil the hardest of any of the autoloaders and are expensive. The Winchester super x, super x2, and super x3 have been excellent and much cheaper than any of the guns mentioned above. I can count on it to shoot and cycle shells regardless of how dirty or cold it is. The browning gold is every bit as good as the Winchesters but is a bit more expensive.
If he is not up to shooting a 12 gauge I would recommend a 20 gauge with same ammo and gun recommendations.
I haven't seen any of these guns above that could not consistently hit a deer size target at 200 yards. I don't think a 1" smaller group at that range is worth sacrificing the velocity, trajectory, or knock down power you gain with these shells. Nor do I think it is fun to have a bolt gun beating a scope into your head with them.
