There are a lot of things to consider and CB covered most of them. In a hunting caliber, you want good penetration, but just the opposite in home defense. A big magnum load can pentetrate several walls into other rooms of the house where family members may be or even through an outside wall and into the neighbors house. If you reload, you can light-load to keep over-penetration in check, but you're still taking a chance. As CB also said, and if your funds will allow it, go with two different guns. A short-barreled scatter-gun may be a little harder to handle in a hurry up situation, but at 3am and coming out of a deep sleep, it'll also be easier to hit your mark should the need arise. Hopefully, you'll never have to find out.