You often hear people say, "The shotgun is the ultimate home-defense firearm," but many don't seem to know why. Such folks assert, "The sound of a pump-action being cycled is enough to scare off most intruders."
Yes, a rational person would hear that unmistakable metallic shunk and go running -- but can we assume the person who just kicked our door down is of sound mind? And, perhaps more importantly, if a truly prepared homeowner cycles his pump-action, it will eject a shell.
There are a variety of reasons to select a gun for home-defense (and the shotgun isn't right for everyone), but its advantages are made obvious with a little math. So I crunched the numbers for you.
It made my head hurt, but I came up with some really intriguing figures. Using the formula Energy =.5 x Mass x Velocity ^ 2, here are comparisons of close-range terminal energies, averaged across a wide range of bullet sizes and velocities.
.45 ACP - 400-450 ft./lbs.
9mm Luger - 330-350 ft./lbs.
.380 ACP - 200 ft./lbs.
.223 Rem. - 1300 ft./lbs.
.30-'06 - 2900 ft./lbs.
12-gauge, 9 pellets 00 buckshot (1.107 ozs.) - 1547 ft./lbs.
So, why is the shotgun so effective? It's equivalent to four simultaneous rounds of .45 ACP. And, get this, each individual .33-caliber, 53.8-grain 00 buckshot pellet packs about 172 foot/pounds--not much less than a round of .380 ACP.
Clearly the average deer rifle packs a heavy wallop, as evidenced by the .30-'06 example. But I wouldn't call it the most practical choice.
The .223 Remington stacks up pretty well, lending credence to the increased popularity of the AR-15 platform as a home-defense gun. The shotgun, however, arguably delivers more of its energy to the target due to the high surface area of its payload.
That's one of the reasons my home is protected by 12-gauge buckshot.
What type of firearm do you keep for home defense? Why did you choose it?