Thursday, October 28, 2010

Parts and Names of Parts

Before we can get into the different types of guns and how they work, we need a list of common terms.

A fully loaded Cartridge consists of four things.  The Bullet is the part that flies out of the front and does the damage.  The Powder is what burns to make that happen.  The Primer starts the powder burning, and the Shell or Casing holds it all together.

Shell casings come in two basic types and two basic configurations.  Handguns tend to use straight wall cases.  This means they are about the same diameter at the top as they are at the bottom.  Rifles tend to use a bottle shape where the neck of the case is just big enough to hold the bullet, while the bottom of the case is much larger.  This allows them to hold more powder, and increases the power of the round.

The other two differences relate to the Rim of the case.  The rim can either stick out slightly, like a small, stubby L, or it can be recessed in so the diameter of the rim is the same as the diameter of the case.  This is the best indicator of whether or not the case was intended for use in a vertically stacked magazine, as used in most modern semi automatic actions for both rifles and pistols.  Recessed rims are called Rimless cases.

Collectively, all of this is called a cartridge, or Round.  It is also sometimes called a bullet, though that is technically the name for just the bit that flies out.  The Bullet can also be called a Slug, though that is an outdated term unless dealing with a shotgun that fires a single projectile.

The Barrel is the most basic part.  It’s also the only truly essential part.  The barrel is just a tube.  It can be a couple of inches long, or it can be a few feet long.  In the case of battleships, it can be several yards long, but the basics remain the same.

The front of the barrel is where the bullet comes out once it’s been fired.  This is called the Muzzle.  The other end is where the round is placed before firing.  It’s called the Chamber.  The inside of the barrel can be smooth, or it can have grooves cut into it in a spiral.  These grooves are called Rifling, and they give the bullet the spin it needs to fly further and with greater accuracy.  All rifles and pistols have rifled barrels.  Some black powder guns do, some don’t.  Shotguns don’t.

Behind the chamber is one of two things, the Breech Face or the Bolt.  The only real difference is that the bolt moves, while the breech face does not.
In the center of the bolt or breech face is a hole for the firing pin.  This is a thin rod that hits the Primer on the back of the round.

The Firing Pin is driven forward by one of many different methods.  Some of these vary by type, and some by manufacturer, so rather than trying to list all of the variations right now, I’ll just say that the firing pin is pushed forward by Force.

This force can be from the Hammer of a pistol, or a simple spring being released.  When the force is in position to be used, the correct term is Cocked

However the force is released, it is the Trigger being pulled that causes it(unless something broke).  The Trigger is the part under the gun that is normally pulled with the index finger.  Some guns use the middle finger, and some actually have other methods, but for the vast majority, it’s the index finger.

I skipped a part.  When the force is ready to be released, there is something that holds it back.  That something is called the Sear.  It’s a little metal bit that has a flat surface on one side, and connects to the trigger on the other.  As the trigger is pulled, the sear moves and allows the spring that drives the force into the firing pin.

That allows Recoil to begin, and that ends this section.

1 comment:

  1. As I was driving home from the Central Station today, I got to thinking about the different parts of a cartridge, and whether or not I had them all right in my head. Then I just got to wondering if you'd covered it here. Awesomely, the answer is yes. Sweet.

    Also, I'm pretty sure there were no particular reasons I was thinking of this, just was, you know how it goes... right?