With a rifled barrel, and shooting the new sabot-type slugs, what you have is actually a large-bore rifle which is every bit the equivalent of some of the .45/70 loadings. These loads make a 12-ga. unnecessary. Usingsuch ammo, I would opt for the 20 every time.

However, if your rules prohibit such ammo, and you are stuck using the old, sorry, Foster-type slugs, I'd be forced to use a 12.

Generally the use of slugs is required on the (mistaken) theory that because such ammo has shorter range, it is thus safer to use. This idea is not only nonsense, but it is untrue when you look at the performance of some of the new "slugs" which perform like rifle ammo. To be "safe", they'd have to restrict you to Foster slugs and prohibit the new ones as well.