Get the 870 express supermag combo. This comes with slug barrel and bird barrel. The supermag has a 3 and half inch chamber, which is nice if you are going to waterfowl, as you can use 3 and half inch shells to reach farther out. You would then use 3" slugs (2 and 3/4" if you prefer). I say the supermag is worth the little more than the standard 3" chamber.