Guns: A primer

With gun safety at the center of public debate, it's understandable that gun-related terminology is flying fast from all directions. So here's a brief compendium of some basics about guns, ammo, and potential areas of regulation.

One quick item: A bullet is the slug that actually moves down the barrel, comes out the end, and delivers a godawful mess of kinetic force to whatever it hits. The shiny brass thing that contains the bullet, the explosives that drive the bullet, and the mechanism that sets it off is a cartridge, or "shell." For convenience sake, I'm sometimes going to say "bullet" when talking about the whole cartridge. Purists beware.

Automatic, Semi-Automatic and Other
The bit of information most likely to be mangled in any reporting on a mass shooting involves the action of a gun. That is, once the gun has been fired, what action does it take to make it fire again?

Many older guns require manual intervention to eject the spent cartridge, load a fresh cartridge, and make the gun ready for firing. Rifles, including military rifles made before the 1950s, are often bolt-action. They work by pulling back on small handle that's attached to a long "bolt." The gun fires, the shooter raises and pulls back the handle, causing the old cartridge to eject, he then shoves the handle forward to bring a new cartridge into place and brings the handle down for firing. A skilled operator can do all this very quickly. Likewise, many shotguns use a pump action. You've probably seen this in movies where Our Hero is going up against a vampire, terminator, or similarly tough beast. Pulling back the handgrip sends a spent shell flying, while pulling it forward again readies the gun for a new shot. It also makes a very cinematic series of clicks.

Automatic and semi-automatic weapons don't require help in tossing out the old shell and loading up the new. They get their energy from the firing of the cartridge, capturing the energy or gases of the spent shell to bring the next cartridge into position. The difference between a fully automatic weapon and one that's semi-automatic is simple: A fully automatic weapon begins firing when the trigger is pulled and keeps firing until you let off the trigger (or run out of bullets), a semi-automatic weapon fires once for each pull of the trigger.

How quickly you can fire a semi-automatic weapon depends partly on the design of the gun, partly on the speed of your reactions. Most of the time, the answer is Very Damn Fast. As in double-digit shots in a second. That's unlikely in a real-world situation, but with a semi-automatic the next shot is there when you're ready.

Fully automatic weapons (which most people tend to think of as "machine guns", though the Army reserves that term for larger weapons) are not legal for private citizens in most cases. You may see fully automatic weapons available to test at a gun range, or in use at special events. But you will rarely see one at all. None of the mass shootings in the United States within recent decades has involved a fully automatic weapon. They are regulated, and that regulation appears to be working.

Semi-automatic weapons are extremely common. Yes, these weapons have been used in many mass shootings, but they are also the most popular type of rifles used for hunting. Semi-automatics have also taken over as the most popular form of shotgun. And of handgun (revolvers are not semi-automatic because the mechanical motion of the trigger positions the next shot).

Some semi-automatic weapons are based directly off fully automatic military models. These guns may have cosmetic differences with their military relatives, but in the same way that a Cadillac and a Chevy may be the same under the sheet metal, they share the same bones as the military guns. They are not fully automatic, and (for the last couple of decades, at least) it has been extremely difficult to convert them to become fully automatic. However, these weapons share many other characteristics with their military cousins. In the United States, there are many variations on a rifle called the AR-15, which is a semi-automatic version of the military M16. Many variations as in dozens, from several different manufacturers. And the AR-15 is just one category. There are semi-automatics that descend from the ever popular AK-47, the Chinese QBZ-95 and several more. These weapons are often able to accept accessories that were originally designed for the military version, or to accept modified versions of those accessories. This includes tripods, extended magazines, laser sights, night vision scopes, and all manner of ridiculous extras that those fearing the looming economic / racial / zombie apocalypse can bolt on to make their guns look meaner and kill more readily. It's these military-derived semi-automatic rifles that are most commonly called "Assault Rifles."

What can we do here? Eliminating or restricting all semi-automatic weapons may seem like the most obvious choice, but it would also be extremely unpopular with hunters, with target shooters, and with gun owners in general. These days, semi-automatic isn't just the first thought of anyone going in to buy a rifle or shotgun, it's almost the only thought. Legislation aimed at all semi-automatic weapons would be difficult to pass, no matter how strong the political tailwind. What can be passed is severe restrictions on semi-automatic weapons based off military models. Nearly half the killers involved in mass shootings over the last 30 years have carried assault rifles. They should be the clear target of any legislation.

The weapon carried in most mass shootings? Semi-automatic handguns. Often more than one. Banning those would be a much tougher fight.

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