Gun Work

How Does a Gun Work?

The Bullet

Many different guns come in many different calibers. This requires different sizes of ammunition to fit them. There also are many other things about a bullet that can differ. A bullet is the metal projectile propelled from the gun when it is fired. Despite the use of different materials and designs, the basic anatomy of a bullet tends to be the same. It is a simple plug of a metal, usually lead, which has been melted down and shaped in a mold to fit the barrel of a gun.

The bullet is just a portion of the whole which makes up a cartridge. A cartridge is what is loaded into a gun prior to firing. The cartridge is made up of a metal shell or cylinder made of brass. This brass shell is shaped to fit into the chamber of a gun as well. It contains a carefully measured amount of gunpowder. One end of the shell is open; the other is closed with a tiny pinhole at the center. The open end is where the bullet is seated by a stamping device that forces roughly 1/4 of the bullet’s length into the top of the shell. The other end of the shell has a small metal button placed over the tiny hole. This metal button is called a primer, and contains a combination of volatile chemicals which can be ignited in a flash if the primer is struck. All together, this makes up a cartridge.

The Gun

There are thousands of makes and models of guns which have been developed and distributed over the years. Basically, they come in two categories, self loading or automatic guns and manual guns. Manual guns could be classified as bolt-action rifles, black powder single-shot muskets, and single- or double-action revolvers. Essentially, what they have in common is that the cartridge does not load itself automatically into the firing chamber of the gun. This must be done by hand, though the actual process varies greatly. An automatic or self-loading gun is different. These come in semi-automatic handguns, semi-automatic rifles, assault rifles, machine guns, submachine guns and machine pistols. What they all have in common is that once the initial cartridge has been loaded from the gun’s reservoir, which is called a magazine, clip, or ammunition belt, depending on the gun, the gun automatically chambers or loads the next cartridge after the previous one has been fired. This process will continue until the gun’s load of ammunition has been expended.

Loading and Firing a Revolver

The two most common guns on the market are handguns–one is a revolver–and the other is a semi-automatic. The revolver is opened first for loading. This may be done several ways. The goal is to expose the rear of the revolver’s cylinder, which contains many separate bullet chambers surrounding a central axis pin. One cartridge is inserted into the rear of each cylinder, typically six in all, and the cylinder is then locked back into place ahead of and above the handle.

The rear-striking hammer, which is at the back of the revolver, is raised. This is done by half pulling the trigger or cocking back the hammer with the thumb. This action turns the cylinder to align the back of the first cartridge with the barrel ahead of the cylinder and the firing pin behind the cylinder. When the trigger is pulled, the hammer falls forward, striking an internal metal aperture called a firing pin. This is a simple metal rod on a retention spring. The pin shoots forward and slams into the back of the primer of the bullet. The impact ignites the primer, which in turn ignites the powder within the brass shell. As the powder burns, it creates a huge amount of expanding gas, which forces the bullet from its seat at the top of the cartridge and propels it down the barrel of the gun. The inside of the gun’s barrel will have a concentric swirling pattern called rifling. This will cause the bullet to spin as it shoots forward out then end of the barrel. This spinning adds stability to the bullet and helps it travel in a straighter line, to impact the target.

Loading and Firing a Semi-automatic

A semi-automatic handgun does not have a revolving cylinder that contains the gun’s ammunition. Instead, it has a hollow handle into which a rectangular metal box called a magazine is placed. This magazine has a flat metal plate at the top with a spring beneath to maintain tension. The plate is pressed down and a bullet is slipped into place between the plate and the surrounding magazine, which has metal prongs that retain the bullet from the sides and back. The only way for the bullet to come out is to be slipped forward. One bullet is stacked atop the other until the magazine is full. It is then inserted into place inside the handle of the gun with a slap, a catch or lever ensuring it cannot fall out.

There is a spring-loaded slide at the top of the gun, behind the barrel, forming the very back of the gun’s chamber. When this slide is pulled back, it cocks the firing hammer at the rear of the gun. When the slide comes forward again, a small metal catchment catches a bullet from the magazine at the bottom of chamber and slides it forward into the breach of the gun’s barrel. Pulling the trigger lets the hammer drop forward, which strikes the firing ping. The firing pin in turn surges forward to strike the primer at the back of the cartridge. The gunpowder in the cartridge is ignited by the primer, which causes a huge expansion of gasses that force the bullet out the barrel of the gun.

The same rifling process occurs with the semi-automatic gun as it does with the revolver. The gasses also cause the slide of the gun to slam backward. Another metal catchment on the slide snags the side of the cartridge that has fired and ejects the empty shell out the side of the gun via a small port. The slide also recocks the hammer of the gun. When the spring in the slide pushes it back forward, it catches another bullet and chambers it, allowing the firing process to repeat again and again. This procedure continues until the magazine of the gun is empty.