There is no firearm more recommended for the new or novice shooter for home defense than the shotgun. Many gun-savvy and experienced shooters also choose this inexpensive and versatile weapon for the bedside or behind the door. There are also more myths, lies and bad advice given to new and old shooters regarding the shotgun as a defensive tool. Birdshot is often recommended because of some misguided idea that it will not go through walls of your home, this same lack of penetration in walls results in lack of penetration in an attacker, leading to a non-incapacitating wound. Don't use it. There is another oft-touted myth of the sound of a pump-action shotgun being pumped scaring away intruders or attackers. One would reasonably argue that if that sound scares them off, then the sound of you simply shouting "I have a gun and I will shoot you," would probably also be effective to frighten them away. Don't buy into such nonsense. The third and most universally misunderstood myth is the idea the shotgun does not need to be aimed, inferring that the shotgun is an "area weapon" of some sort. This could not be further from the truth. With the shortest 18-inch cylinder bore barrel at across the room distances, the shotgun can group its shot within a 2-inch circle with reduced recoil loads, even the loosest shot pattern is only about six inches at this distance. These guns require aiming, just as any other. Do not believe otherwise.
When choosing defensive ammunition, the number one factor to consider is reliability. If the ammunition does not function in your gun it is of no use. This point is most applicable to semi-automatic shotguns, as some will not function reliably with certain loads. No matter what ammunition you choose it is of the utmost importance that you "pattern" your load in your gun, especially at the distance you may use it. You must know the capabilities of your defensive system. Defensive use of the shotgun in the home requires that any load chosen limits penetration while still providing incapacitating performance. We will be basing our defensive performance standards and the selection defensive ammunition on the criteria of adequate penetration of at least 12 inches and pellet distribution in gelatin testing.
The 12 Gauge is the most popular shotgun caliber, and that makes it very easy to find many acceptable defensive loadings. The best ammunition, using our standards, for home defense is the standard velocity Remington AMM-8174, with the Winchester 65081 just barely behind. The next best 12 gauge ammunition would be the harder recoiling Winchester 2 3/4 inch Magnum #1 Buck load, with 20 copper-plated, buffered, hardened pellets. This is a very tight patterning load, but nearly impossible to find anywhere for sale. The third best choice for defensive use would be standard 2 3/4-inch 00 buck loadings from Federal AMM-843, Remington AMM-817 or Winchester 57941. Any reduced recoil load, any magnum load or any load containing hardened buckshot may over-penetrate and should be kept in mind if this is of any concern. The final choice is any 2-3/4inch magnum load that uses hardened, plated and buffered #4 Buckshot such as the Federal 65533.
As for 20 gauge, defensive loads are much harder to find and you may not be able to be as choosey on your ammunition selection. The best available is the relatively hard-recoiling Federal 3-inch Magnum #2 Buck(65656). For those who are recoil sensitive, Remington offers a #3 Buck load in a 2-3/4 inch shell (AMM-848) that patterns the tightest in most shotguns. Winchester 2-3/4 inch magnum #3 Buck load (65084) is the next best choice.
For .410 loads, your choices become even fewer. Any Buckshot or non-expanding slug design should be adequate for home defense. Winchester makes 2-1/2 inch AMM-861 and 3 inch #000 Buck loads (11082). Brenneke makes some of the best slugs on the market (37898) and Winchester has the Super-X 3-inch slug load 14319.