Other Uses
Caps have occasionally been used in toys other than cap guns where an explosive effect is desired. One example would be the "Thunder Punch" version of the He-Man action figure from the original 1980s Masters of the Universe toy line. Ring caps were placed in a "backpack" integrated into the figure, which contained the striking mechanism for the caps (as well as tiny vents to allow smoke from a triggered cap to escape). This mechanism was triggered by drawing the figure's spring-loaded right arm back and releasing it to swing forward; the explosion of the cap was intended to simulate a thunderous noise caused by the supposed superhuman power of the character's punch.
Another example is a relatively new type of Airsoft, called Hybrid Guns. Hybrid guns use small round BBs in the tip of a casing, usually designed to mimic that of its respective magazine. The caps are placed behind the casing. In electric models, the caps are burst, and the pressure is used to propel the BB forward in a manner similar to real firearms. The leftover energy is then sometimes put to use simulating recoil and a blowback system that ejects the casings.
Also, caps are used in Chinese toy flare guns. The cap propels one or two pyrotechnic star loads in flare cartridge (firearms).
Another use is in so-called "cap bombs"; devices roughly in the shape of an aerial bomb that contain a firing mechanism in the nose capable of holding a single cap, either plastic or paper (cut from a strip), though types are not interchangeable due to the mutually exclusive designs. These devices are either dropped or tossed up into the air, where fin stabilizers act to point the nose (and firing mechanism) downwards, where it detonates loudly upon striking a hard surface.
Read more about this topic: Cap Gun