There are many theories and more importantly, tons of inaccurate information floating around about which round to use for home defense. In this short article, all stats are based on 2 3/4 inch 12 gauge loads and have been compiled from various sources.
The first mistake that is often made is the decision to load birdshot for home defense regardless of shot size. At extremely close distances, it may be enough to stop an intruder. When it comes to defending my family, may is not good enough. Birdshot is known to do an extreme amount of superficial damage to the first few inches of tissue but without the penetration necessary to incapacitate an intruder. Birdshot can penetrate as little as 3 to 4 inches before factoring in clothing and while it may minimize damage to your walls, it won't necessarily save your life. Winter clothing can reduce this damage even further. There are numerous articles where home intruders have survived birdshot wounds to the torso at almost point blank ranges. A google image search for "birdshot wound" will show links to many survivors.
#8 Birdshot - Average 4 inches of penetration - [Source]
Looks painful, but clearly still alive.
What about over penetration you ask? Anything that won't penetrate a sheet of drywall likely won't even kill your cat. The simple fact is that penetration is required in order to be effective. The FBI recommends at least 12 inches of penetration in calibrated ballistics gel for a potentially lethal shot. Anything that will penetrate 12 inches of ballistics gel will go clean through several walls. If you have a wife and 8 kids scattered around your house, consider establishing defensive locations in your home with a safe backstop before deciding to use less lethal rounds.
The fact that you're using deadly force in the first place means that the intruder is armed as well. Dropping the intruder as quickly as possible to minimize return fire should be the highest priority, not the worry about damage to your walls.
When it comes to selecting the most effective buckshot size, we're presented with the following options:
|Shot Number||Number of Pellets||Pellet Diameter (Inches)||Average Pellet Weight (Grains)||Cross-Sectional Displacement|
Historically, 00 buckshot has been the most common round for home defense. It is primarily used by military and law enforcement due to its low pellet count. Less pellets means less projectiles to account for, and that's an important consideration for law enforcement.
Recent testing however has shown #1 buckshot to be the perfect balance between the largest amount of damage dealt while still being capable of enough penetration for a lethal wound (12+ inches). The difference between .33 cal and .30 is fairly minimal, while an increase of pellet count from 9 to 16 is substantial. The large increase in pellet count constitutes an increase of cross-sectional area displacement of almost 50% while giving up little penetration (approx 20 inches vs 17 inches). The increase in pellet count combined with the decrease in penetration has shown an overall increase in wound tract damage of over 75% according to ballistic gel tests. This means more internal damage per shot.
#1 Buckshot - Average 17 inches of penetration - [Source]
Still, it is the general consensus that anything #1 buck or larger is acceptable for home defense. This includes #1 buck, 0, 00, and 000. Many people prefer #4 buckshot due to the 27 pellet count however for me, the substantial pellet weight reduction from 40 grains down to 20.6 grains is just too extreme. At this point we're talking about a pellet weight of almost half a standard .22LR round and the 14 inch penetration in ballistic gel before factoring in clothing, is approaching the borderline a bit too close for my comfort. Will it work? Most likely. I personally just feel more comfortable using something that exceeds the standards by a decent margin rather than barely meeting them. For that reason, I recommend #1 buckshot with 00 buck being a close second. Buckshot sizes 0, #2, and #3 have not been considered due to the extreme rarity of these rounds.
As always though, shot placement is the key. Make sure you get lots of range time in and get lots of practice with your weapon of choice.
Questions or comments on this article can be discussed here.