Well, I suppose I could try to teach you how to shoot, but frankly, that's more of a hands-on job. Contact the the NRA and ask about training. (Yes, that NRA. Politics is only a small part of their activity; they were founded (in 1871) as a marksmanship and safety training organization.) Offline, if you're just getting started, I recommend Beginner's Guide to Guns and Shooting, 2nd Edition (or later) by Clair F. Reese. It is very well written and organized, covers all types of guns (even old-fashioned blackpowder guns and machine guns), and stresses safety a lot without being condescending. For more advanced training, see my Front Sight Firearms Training Institute page.
In the meantime, here are a few definitions to help you understand what people mean when they talk in gun terms. This list is not intended to be an exhaustive technical reference for the firearm enthusiast, only a brief tutorial to enable the layman to understand terms likely to be used (or rather, misused) by the media. My hope is that with the aid of this list, laymen can spot many of the errors of the media, and outright lies of the anti-gun lobby. For ways to spot more errors and lies, see my page on the political side. (Note: both pages are very much Under Construction.)
Terms listed so far include:
ACP
Armor Piercing Bullet
Assault Rifle
Assault Weapon
Automatic
Blackpowder
Bullet
Caliber
Carbine
Cartridge
Clip
"Cop-Killer" or Teflon-Coated Bullets
Frangible or Pre-Fragmented Bullets
Fully Automatic
Gun Show Loophole
Gunpowder
Machine Gun
Magazine
Pistol
Repeater, or Repeating Firearm
Round
Semiautomatic, or Semiauto
Smokeless Powder
Saturday Night Special, or Junk Gun
Submachine Gun, or SMG
Suppressor, or Silencer
X-Ray-Invisible Plastic Terrorist Gun
And now, on to the definitions:
Note that assault rifles and "assault weapons" differ mainly in that the former are fully automatic and the latter are semiautomatic. This may sound like a picky technical difference, but it's huge. Functionally, assault rifles work like machine guns (i.e., can "spray bullets"), while so-called "assault weapons" are no different from many very common hunting or target rifles. The term "assault weapon" was coined by Josh Sugarmann of the (anti-gun) Violence Policy Center, precisely to engender exactly such confusion. This is not an idle accusation; he proudly boasts of fooling so many people with this ploy. Furthermore, contrary to the propaganda that they are unsuitable for sporting purposes (which is not what the Second Amendment is about anyway), they are very frequently seen at target ranges and on hunts.
(There are some quirks, however, in that some bullets are, or historically were, "heeled". This means that the bullet has a sudden small narrowing step as it enters the casing, usually resulting in the bullet being of the same diameter as the casing. Nowadays, .22 is almost the only heeled bullet in common use. .38 bullets used to be heeled, but are not any more; this is why .38 Special and .357 Magnum bullets are identical (at .357" in diameter), though the .357 Magnum cartridge is slightly longer.)
Also, the term is used differently in reference to naval artillery. In that usage, it refers to, roughly, the length of the barrel divided by its diameter. Thus, a naval artillery piece that fires five-inch (diameter) shells and has a ten-foot (120 inch) barrel, would be 24 caliber, while another piece firing the exact same shells, but having a barrel seven and a half feet long (90 inches), would be 18 caliber.
In this usage, it is often called a round. A shotgun cartridge is also often called a shell.
In older guns, this may refer to a paper casing, simply holding gunpowder and a bullet, either to be inserted whole into a gun, or to be torn open and used separately (the main value being the pre-measurement).
A particular type of cartridge may be referred to by several different means, but usually includes the caliber. There may be additional modifiers tacked on to designate how much gunpowder should be inside the casing (such as .30-30), how long the case is (usually in millimeters, such as 7.62x39), the year the military (usually U.S. Army) officially adopted it (such as .30-06), who invented it (such as .40 S&W, by Smith & Wesson), Magnum (which usually, but not always, means it is more powerful than previous ones), the particular gun it is meant for (such as 9mm Luger), official adoption by some important organization (such as .308 NATO), or anything else to distinguish it from others of the same caliber (such as .38 Special or .22 Long Rifle).
Generally, the higher/larger the caliber, the more powerful the round. For instance, .45 ACP is much more powerful than the 9mm (which is about .36, in standard caliber terms). However, some rounds may be more powerful than ones of a larger caliber. That is usually because the more powerful one has more gunpowder inside it. Frequently such a comparison is between a fat handgun round and a skinny rifle round. Rifles have much more room for a long casing, which may also be "shouldered", meaning that the part of it in back of the bullet is fatter. Both of these mean that it can hold more gunpowder.
To top it off, when the media intended to come out with this grossly distorted story, many police departments and organizations begged them not to. The two main results of the story were first the public receiving the false impression that there was such a thing as a "cop-killer" bullet, and second the criminals becoming aware that police often wore body armor. This latter meant that the criminals started shooting for the head instead, tripling the annual rate of police duty fatalities, as the police had feared.
This started a legislative rush of poorly thought out bills aimed at the (nonexistent) "cop killer" bullets. Most of these were worded so as to outlaw any ammunition capable of penetrating a bullet-resistant vest. Unfortunately, the vast majority of rifle ammunition is easily capable of that. Fortunately, the bills were amended to pertain only to handgun ammunition. (After all, use of a rifle in a crime is vanishingly rare, despite all the propaganda about so-called "assault weapons".)
KTW bullets were never put into mass production, and were never even intended for sale to the public, let alone actually sold to the public. To the best of my knowledge, there has never been another attempt at this approach.
More recently, you may have heard some commotion about something called "Black Rhino" ammo, that allegedly penetrates body armor and then fragments into thousands of razor-sharp fragments. This was a hoax! The man who claimed to make them refused to submit samples to any gun publication for testing, is a major donor to Handgun Control Incorporated, and did not have the required federal license to manufacture ammunition. His non-Black "Rhino" bullets, which he also claimed were unusually deadly, turned out on closer inspection to be a readily-available brand of frangible bullet. (This illustrates quite well the depths of lying to which the anti-self-defense lobby is readily willing to stoop to manipulate public emotion.)
The original was the Glaser Safety Slug. This consisted of a large number of small pellets in a plastic capsule. The reason for this was to prevent doing damage in case of a miss -- in particular, for use by Air Marshals aboard aircraft, where a hull puncture could be disastrous. For much the same reason, they are often used for home defense, so that a miss will not penetrate a standard interior wall, with enough kinetic energy left to be likely to seriously injure innocents in the next room or apartment. Contrary to the media hype about nasty wounds, this type of bullet tends to create rather shallow wounds -- and no wounds at all, other than a bruise, if the person is shot through clothes as heavy as an ordinary leather jacket.
More recently, owners of steel targets have turned to frangible ammunition to (again) reduce damage. There are several types of frangible bullets used for this purpose, including the "lots of shot in a capsule" idea again, "sintered" bullets (metallic powder compressed under high pressure to form a temporary solid), ones pre-scored to break apart into many sections upon impact, powder inside a scored cylinder, and many more. Note that the powdered metals are always non-toxic metals such as tin and iron, not lead, due to environmental concerns. Since they are often used indoors, they also usually have lead-free primers.
(Note that any firearm capable of fully automatic fire is subject to the National Firearms Act of 1934, often referred to as NFA '34. This means that in order to own it (legally), you must pass a background check roughly similar to the one done for a Department of Defense SECRET-level clearance, pay a $200 "transfer tax" per item, declare to the BATF where you intend to keep each item, and (more or less) waive your Fourth Amendment (search) rights for that entire dwelling or place of business. Since passage of NFA '34, a grand total of one crime has been committed in the USA with a legally owned fully automatic firearm -- and that was by a police officer with a departmentally-owned weapon. It should therefore be screamingly obvious that further controls on them are not needed!)
These terms are also often applied (again, almost exclusively by anti-gunners) to any small gun, or gun with a frame made of light materials such as polymer or aluminum alloy -- even ones of excellent quality -- just to smear them. The smearing of light-framed guns is often disguised by legislating about low density, melting point, or tensile strength, such as a ban NJ attempted in 1996 on guns that melt below 700 degrees F. Only the tensile strength is at all relevant, and the tests are always set well beyond the level needed for safe firearm use.
Small and/or light guns are often carried by concealed-weapon permit-holders (who, in most states, have been thoroughly investigated by the police and found squeaky-clean), or as "backup" by police. Many polymer framed guns are popular with police even as primary duty weapons, such as the Glock 17. Many others, such as those by SIG-Sauer or H&K, are famous for high quality (and often high price as well). The fact that most laws against "junk guns" exempt police should clue you in that they are not of "junk" quality -- who (other than criminals) would want the police armed with junk?
The term itself is of racist origins, referring to an old song titled "Niggertown Saturday Night", implying that a very cheap handgun is all that a black person can afford -- and that they would be quite likely to use it in a crime of drunken violence on a Saturday night. (Note: reporting this origin does not mean that I agree with it!)
In the USA, these are covered by the same federal law as fully automatic guns (not illegal, but heavily regulated), so most Americans think of them as useful only for spies, assassins, and such unsavory folk. In most other countries, however, it is highly encouraged to use them for hunting, target practice, etc., so as to reduce noise pollution! (Of course, in most other countries, though the suppressor may be easy to get, the gun to put it on may be another story entirely....)
They are generally found on pistols, sometimes on rifles, on the occasional submachine gun, and once in a blue moon even on a shotgun. They are almost never found on revolvers, since the gap between the cylinder and the barrel allows gas to escape there at high velocity (and therefore high noise). There is, however, an old and fairly rare line of revolvers (Russian, late 1800s), in which the cylinder pressed forward during firing, so that the catridge casing actually entered the barrel, forming a gas-tight seal as in the chamber of a pistol.
This term was originally applied mainly to the Glock 17, which was smeared as "a gun only a terrorist could love". Many US and foreign police departments, and foreign militaries, now use it as their standard duty sidearm. The same can be said for many similar pistols, such as the SIG 226 (widely used by assorted USA federal police). Other similar ones are popular in target shooting or personal defense.
For more terms, see my presentation titled "Guns, Terms, and Wheel(locks)" (open it with Open Office), or Father Frog's Glossary of Terms Relating to Firearms.
If there are any terms you would particularly like to see added to this list, please email me.
Other online firearms technical information resources include: