How Paintball Works

The Way of the Gun

Players lie in wait for members of the rival team. Winning in paintball requires a combination of weapons skill and strategic planning.
Players lie in wait for members of the rival team. Winning in paintball requires a combination of weapons skill and strategic planning.
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In the last section, we saw that paintball guns propel paintballs with a quick burst of compressed gas. In the animation below, you can see how this process occurs in a conventional pump-action gun.

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In the middle of the gun, there is a long valve tube. This runs from the barrel, where the paintballs are loaded, to a chamber at the back of the gun, where the gas cartridge is connected. Along this path, the tube passes through the bolt, a spring, the hammer and, at the gas-intake end of the gun, the valve seat. At the barrel end of the gun, the tube is always open. But the openings at the other end, which are positioned along the sides of the tube, are blocked off by the surrounding valve seat. The tube is held in position by a cup seal, pushed against the tube by a small spring and the pressure of the gas in the chamber.

When the gun isn't cocked, the bolt extends into the barrel, blocking the entryway for the paintballs. To cock the gun, the shooter pulls the bolt backward, pushing against the spring so that the bolt butts up against the hammer. This motion does two things:

  • As the bolt slides back, the ammunition intake opens, and a paintball can fall into the barrel.
  • On the bottom of the hammer, there is a small spring-loaded latch called a sear. The sear, which pivots on a tiny pin, catches hold of the bolt when the bolt is pushed against the hammer. In this way, the sear binds the bolt and hammer together so they move as one unit.

After pulling the bolt back, the shooter pushes it (along with the hammer) forward. To fire the gun, the shooter pulls the trigger. The trigger pushes up against the back end of the sear, so the front end moves down. This releases the hammer from the bolt, and the spring rapidly propels the hammer backward. As the hammer moves backward, it pushes on a raised lip around the valve tube. This propels the valve tube backward with a burst of force that is greater than the forward force exerted by the rear spring and gas pressure. The valve tube is pushed back for an instant until the spring pushes it back into place. In this instant, the side openings on the tube are exposed, and the pressurized gas can flow through to the barrel. This burst of gas is strong enough to propel the paintball forward at a good rate of speed.

In autococker paintball guns, an adjustable valve automatically diverts compressed gas to the front of the gun after it is fired. This gas serves to push the bolt back again, so the gun recocks. This way, the shooter doesn't have to recock the gun with every shot. Automatic guns use the compressed air, or in some cases an electric motor, to continually recock and fire the gun as long as the trigger is held down. To find out more about these sorts of guns, check out

As paintball has evolved, the equipment has become more and more sophisticated. In the next section, we'll look at the history of paintball to find out when and why the game was invented. We'll also look at how the game is played and at other uses of paintball equipment.