A CAP gun is a type of toy gun that makes a loud popping sound when the trigger is pulled. It is usually made of plastic and uses a small percussion CAP to create the sound. A RAY gun is a type of fictional gun that emits a beam of energy, typically used in science fiction stories. A Nerf gun is a type of toy gun that fires foam darts or balls. SPRAY guns are used to SPRAY paint, varnish, and other liquids onto surfaces. RADAR guns are used to measure the speed of moving objects. Hired guns are people who are hired to do a job, often involving violence. STAPLE guns are used to fasten materials together with staples. STUN guns are non-lethal weapons that use electric shock to incapacitate a person. POP guns are toy guns that make a popping sound when the trigger is pulled. ZIP guns are homemade firearms that are made from various materials. The BREN gun is a light machine gun that was used by the British military during World War II. RIOT guns are shotguns that are used by law enforcement to disperse crowds. The Sten gun is a submachine gun that was used by the British military during World War II. SQUIRT guns are toy guns that shoot water. The Gatling gun is a type of machine gun that was invented in 1861.