 In the 1840s and 1850s, the percussion cap was first integrated into a metallic cartridge, which contained the bullet, powder charge and primer.By the 1860s and 1870s, breech-loading metallic cartridges had made the percussion cap system obsolete.Today, reproduction percussion firearms are popular for recreational shooters and percussion caps are still available (though some modern muzzleloaders use shotshell primers instead of caps).