I am in the process of helping my parents train with a handgun for some home protection. After much talk about shotguns falling on deaf ears I finally convinced them to get a Shotgun as well. My original plan was to get a Remmington 870 in 20 gauge BUT then I read the below article. I don't understand why the 870 would be so loved in 12gauge and not in 20gauge (my plan for my parents). Any incite would be appreciated. I guess the Mossberg 500 Special Purpose would not be a horrible choice either.
If you are new to shotgunning and considering getting one for self-defense I strongly urge you to buy the reliable and reasonably-priced "Mossberg 500 Special Purpose" 18.5" barrel 20 gauge pump shotgun (catalog #50451). This tried-and-true workhorse is the standard shotgun of the U.S. Armed Forces and costs a little over $200. You'll be much happier with the lighter-kicking 20 gauge than the 12 gauge version used by the military, and - most importantly - you'll shoot the 20 more accurately and rapidly.
For an in-depth look at the 20-versus-12 gauge issue I recommend all shotgun owners (and potential shotgun owners) read 'Stressfire II: Advanced Combat Shotgun' by Massad Ayoob. Perhaps I am beginning to sound like a broken record on the theme of Ayoob's books, but once you've read them you'll understand why I recommend them so highly (and repeatedly). Note: Ayoob dislikes the 20 gauge Remington 870 pump shotgun and recommends you choose the Mossberg 500 in 20 gauge for general self-defense and home-defense use. So do I.