There’s a lot of discussion out there, weighing the pros and cons of using birdshot or buckshot for a home defense situation. It seems to boil down to varying opinions on either the uncertain stopping power of birdshot, or the danger of over-penetration with buckshot. Here’s an interesting take on the subject:
“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. This is too shallow to reliably affect an assailant’s heart or major cardiovascular blood vessels. Because the wound trauma produced by birdshot is not decisively effective, a quick stop to deadly violence is not guaranteed.
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.”