Caps Use Gunpowder
The "caps" used by a cap gun come in a variety of forms. Some caps, common on toy revolvers, feature six or eight small tubes of tightly packed gunpowder in a circular plastic configuration, while others offer a similar setup in a straight plastic line that can easily be pushed through the gun. Still other caps come in a long paper roll that contains several "blisters" of tightly packed gunpowder. Regardless of the type of cap used, all cap guns operate on the same principle.
Cap Guns Use a Hammer
When caps are loaded into a cap gun, the small amount of tightly packed gunpowder is aligned with a flat, hard striking surface. As the user fires the cap gun, a small, metal, spring-loaded hammer pulls back along with the trigger until it reaches its maximum extension. At the end of its extension, the hammer releases to quickly and solidly make contact with the striking surface. As the resulting force crushes the packed gunpowder, the pressure causes the gunpowder to ignite and explode out of its container.
Cap Guns Seem Real
When the hammer strikes the gun powder, the result is a small explosion similar to a small caliber pistol or rifle. Because the cap gun uses actual gun powder, the explosion produces a flash, smoke, and smell that is nearly identical to a real firearm, though the sound is somewhat softer (because less gunpowder is used) and sharper (because the solidity of the firing chamber on a real firearm slightly muffles the explosion). Still, some high quality cap guns very accurately reproduce the sights and sounds of an actual firearm.