A blank is a type of cartridge for a firearm that contains gunpowder but no bullet or shot. Blanks use paper or plastic wadding to seal gunpowder into the cartridge. When fired, the blank makes a flash and an explosive sound (report), the wadding is propelled from the barrel of the gun, and the firearm's action cycles. Blanks are often used for simulation (such as in historical reenactments, theatre and movie special effects), training, for signaling (see starting pistol), and cowboy mounted shooting. Blank cartridges differ from dummy cartridges, which are used for training or function testing firearms; these contain no primer or gunpowder, and are inert.