Picture a railroad spike, held vertically as if to be pounded into a railroad tie. Now picture a 14 pound bowling ball poised 35 feet above the spike, and then let drop straight down to hammer the spike down into the ground.
The energy m*g*h works out to about 600 joules, a typical energy for the .40 S&W bullet. On this picture it’s the third from the right. It’s also the caliber of the pistol I own.
Image courtesy Wikipedia
Now the damage the spike would do and the damage the bullet would do are two different things, but the comparison is not a terrible one. The energy of the bullet will be transfered to the body by exerting a force through a distance. While the speed and acceleration will be different, energy is the main quantity of interest and so the bowling ball provides a rather dramatic comparison as to just exactly how much you don’t want to be hit by a shot. The .40 S&W is probably the second most popular pistol cartridge after the 9mm round, which is the second from the right. Typical muzzle energies for the 9mm are around 480 J, or that bowling ball being dropped on the spike from 27 feet.
And you can go the other way up through the calibers to the .44 Magnum of Dirty Harry fame (second on left). Energy ranges widely for this one depending on the actual weight of the bullet, but 2000 J is perfectly plausible. That’s a 116 foot drop for the bowling ball onto the spike. Make my day indeed. It’s not the most powerful commercial pistol cartridge out there, but it’s the most powerful you’re likely to see in a gun for anything other than explicitly firing ridiculous specialty calibers.
Rifles? They’re several steps up, and while there’s many, many calibers out there I’ll only mention two. The .30-06 of WWII and hunting rifle fame is usually in the vicinity of 4000 J, or 230 feet worth of bowling ball drop. This is considerably more powerful than the ammunition currently used by US soldiers in their M16 rifles, as modern tactics generally prefer volume of fire over the strength of one particular powerful but bulky shot.
If you want a truly preposterous round, there’s the .50 BMG. Legal in most states (And why not? It won’t kill you any deader than a .30-06, each shot is about $4, and the guns that fire it are absurdly bulky.), it has a muzzle energy of an astonishing 13,000 J, or about 750 feet worth of bowling ball drop. But if you’re in an enemy APC it could ruin your whole day. Here’s it’s picture. It’s the big one. An M16 fires the second from the right.
Also from Wikipedia
The lesson to take away from all this? A Chevy Suburban at interstate speeds has something like a hundred times the kinetic energy of the .50 BMG. Like a car or truck, a bullet is a tool that is dangerous if not treated with respect. When you use them, be safe!