“…[once] a home defense shotgun has been put together, the question remains: What should we feed it?

First, let’s ask ourselves why a shotgun is being used for home defense. Understanding that will help us make the ammunition choice. A shotgun has some advantages that make it desirable as a home defense weapon.

While any firearm powerful enough to use for defense will penetrate most walls, shotguns are slightly less likely to over penetrate.

A shotgun has the ability to fire a shell with multiple projectiles, increasing the likelihood of a solid hit and thus of stopping the threat. Some say the ominously large bore and unique sound of the action tend to make bad guys choose another activity… one far away from you and your family.”

http://carteach0.blogspot.com/2009/02/home-defense-shotgun-ammunition-basics.html