Later flintlock shotguns and percussion cap guns were used. It used a waterproof paper cartridge ignited with a percussion cap. This was a single shot, muzzle-loading gun that used the percussion cap firing mechanism. These still used a separate percussion cap. The explosives in the percussion cap are a lead styphnate and tetrazene explosive mixture. The percussion cap was placed over the nipple. The first two models of the Chassepot still used percussion cap ignition. Using this discovery, the percussion cap was created. His cartridge consisted of a percussion cap with a bullet attached to the top. By the 1860s and 1870s, breech-loading metallic cartridges had made the percussion cap system obsolete. In modern systems, this is almost always a percussion cap. The only propellant substance contained in the cartridge is the percussion cap. The standard pressure sensor used a percussion cap to ignite it. The percussion cap, when struck by the hammer, ignited the powder charge.