There's been discussions in a few recent threads in which the OP is looking for suggestions for their "new" (to them) self/home defense shotgun. The motive seems to be looking for reassurance that their choice will be adequate in protecting themselves, which is obviously the #1 goal. Folks, while certain cartridges are "fun" to shoot/plink with, in regards to shotguns, reasonable cartridge selection for home defense is extremely limited if not exclusive. CHOOSE THE 12 GAUGE!!! Here's why: (paraphrased Internet Armory) The shotgun is, by far, the deadliest and most formidable, effective firearm ever created for short range personal defense. No other firearm will devastate, disable, or discourage an aggressor as reliably as a shotgun. No other firearm is as likely to hit an assailant as a "scattergun" loaded with buckshot. Shotgun ammunition consists of three general types: * Buckshot Load: A shotgun shell loaded with large diameter lead balls. It is used for big game hunting and for self defense. For a standard 2-3/4-inch shell in 12 gauge, the number of balls or pellets ranges from eight .36-inch balls in "000 buck" to 27 .24-inch balls in "# 4 buck". Please note that "000 buck" is pronounced "triple ought buck" and "00 buck" is pronounced "double ought buck", not "zero zero zero buck" or "oh oh buck". Again, it's tradition. Avoid being ridiculed as a peasant. * Birdshot load: A shotgun shell loaded with small diameter pellets used for hunting game birds and waterfowl. Stopping power is poor, except when used at close range, out to 20-30 feet or so. It is only recommended for personal defense in the home, when adjacent properties might be affected by the use of buckshot loads. * Rifted Slug Load: A shotgun shell loaded with a solid lead bullet. Slugs are huge hunks of soft lead, grooved on the sides to promote rotation and stability in flight. They have enormous stopping capability. Because slug loads must be carefully aimed like a rifle or handgun, their use ruins the shotgun's main advantage: superior hit probability. Recommendations regarding preferred shotgun ammunition for self defense follow. .410 Gauge: One Shot Stopping Success: Data Not Available Recommended Cartridges: Federal "Classic": slug 88 grains Winchester "Super X": slug 88 grains This weak caliber is not really a decent self defense round, even when loaded with slugs. Never use birdshot. 20 Gauge: One Shot Stopping Success: Data Not Available Recommended Cartridges: Federal "Classic": 3-inch #2 buckshot 18 pellets Winchester "Double XX" : 3-inch #3 buckshot 24 pellets Remington 2-3/4-inch: #3 buckshot 20 pellets The 20 gauge is an excellent caliber for self defense. It is particularly well suited to those of smaller stature and those that dislike the blast and recoil of the 12 gauge. When compared to a 12 gauge, the 20 gauge delivers 75% of the lead with a recoil that is 40-50% less. This is equivalent to the ballistic force of being hit with two .44 Magnum rounds simultaneously. Reduced recoil of the 20 gauge is conducive to accurate, rapid shots. Recommended shells include #4, BB, or larger hunting loads. Fill the balance of the magazine with #3 buckshot for insurance, due its proven ability to penetrate. Buckshot is preferred over birdshot and slug use in the 20 gauge. For those who insist on slugs, use Federal "Classic" rifled slugs. Effective slug use requires careful aiming with a shotgun equipped with rifle sights. Few 20 gauge shotguns are so equipped. 12 Gauge: One Shot Stopping Success: 81-96% (Actual) Recommended Cartridges: Federal "Tactical" 2-3/4-inch 00 buck 96% Remington "Magnum" 3-inch 00 buck 94% Winchester 2-3/4-inch 00 buck 94% Federal 2-3/4-inch 00 buck 89% Remington 2-3/4-inch 00 buck 88% The 12 gauge shotgun is the most devastating and lethal weapon yet devised for inflicting rack and ruin at close range. A safe bet for ammunition selection is to use the 2-3/4-inch 00 buckshot load. The impact of one of these shot shells is essentially equivalent to getting hit with a nine round burst from a submachine gun. It is probably a good idea to avoid the 2-3/4- and 3-inch "Magnum" loads. Their brutal kick makes them a bad choice, and little is gained over the stopping power of standard rounds. Controllability is important, and standard 12 gauge shotgun shells have plenty of kick already. Some shooters prefer #4 or #1 buckshot over 00 buck. Real world one shot stopping success of the #4 buck is a respectable 81-83%. Data hasn't been collected for the #1 buck, but its performance should be even better. The one ounce slug, fired from a 2-3/4-inch Federal, Remington, or Winchester shell, has a one shot stopping success of 98%. A deer barrel with rifle sights is the appropriate platform for this round. It is not the best choice for self defense because aiming becomes the critical factor in effective shot placement. The high probability of scoring hits, an advantage associated with buckshot loads, is lost. Slugs also have ferocious recoil and tend to over penetrate. Although birdshot is not as lethal as buckshot, even at close range, it may make sense for home or apartment defense where the opportunity exists to injure or kill innocent people behind thin walls in adjacent rooms. For defending a single family home, buffered by land, 00 buck is preferred. The choice for birdshot loads is BB or #4 birdshot. Out to a range of 30 feet or so, birdshot is essentially a solid column of lead pellets. Stopping power may not be sufficient, however, due lack of penetration potential. At close range, birdshot can destroy a great deal of tissue, producing a gruesome wound. The depth of the injury, however, will likely be six inches or less. Buckshot loads, on the other hand, will exhibit penetration on the order of 12 inches or so, a depth sufficient to intersect vital blood distribution structures and terminate aggression. Some misconceptions may exist regarding the spread of shotgun pellets or balls. It is not enough to merely point the shotgun in the general direction of an assailant and let fly. Birdshot or buckshot does not create a huge cone of death and destruction that devastates everything in its path. Rather, for a defense or "riot" shotgun with an 18- to 20-inch open choked "improved cylinder" barrel, the pellets will spread out about one inch for every yard of range traveled. Across a large room of 18 feet or so, the spread will only be about 6 inches, a circle as big as a coffee cup saucer. At 50 feet, the spread will only be about 16 inches, the size of a large pizza. It is obvious from this information that a shotgun blast will not incapacitate multiple assailants at close range. The shotgun must be skillfully aimed and fired. Aiming is just not quite as precise as that required for a handgun or autoloader to score multiple hits on an aggressor. The massive firepower of the shotgun will likely produce a favorable outcome in any self defense encounter. 10 Gauge: One Shot Stopping Success: Data Not Available Recommended Cartridges: For this "cannon", anything.