<P> Most shotgun shells are designed to be fired from a smoothbore barrel, but dedicated shotguns with rifled barrels are limited to sabot slugs . A rifled barrel will increase the accuracy of sabot slugs, but makes it unsuitable for firing shot, as it imparts a spin to the shot cup, causing a centrifugal force that makes the shot cluster disperse . A rifled slug uses rifling on the slug itself so it can be used in a smoothbore shotgun . Specialty shotgun ammunition includes non-lethal rounds available in the form of slugs made of low - density material, such as rubber . </P> <P> Early shotgun shells used brass cases, not unlike rifle and pistol cartridge cases of the same era . These brass shotgun hulls or cases closely resembled rifle cartridges, in terms of both the head and primer portions of the shotgun shell, as well as in their dimensions . Card wads, made of felt, leather, and cork, as well as paperboard, were all used at various times . Waterglass was commonly used to cement the top overshot wad into these brass shell casings . No roll crimp or fold crimp was used on these early brass cases, although roll crimps were eventually used by some manufacturers to hold the overshot wad in place securely . The primers on these early shotgun shells were identical to pistol primers of the same diameter . </P> <P> Starting in about 1877, paper hulls started to replace brass shotgun shells . Paper hulls remained popular for nearly a century, until the late 1960s . These shotgun shells using paper hulls were nearly always roll crimped, although fold crimping also eventually became popular . The primers on these paper hull shotgun shells also changed from the pistol primers used on the early brass shotgun shells to a primer containing both the priming charge and an anvil, unlike rifle and pistol ammunition, making the shotgun shell primer taller . Card wads, made of felt and cork, as well as paperboard, were all used at various times, gradually giving way to plastic over powder wads, with card wads, and, eventually, to all plastic wads . Starting in the 1960s, plastic cases started to replace paper hulls for shotgun shells; by the 1980s, plastic cases had become almost universal . </P> <P> Today, modern shotgun shells typically consist of a plastic case, with the base covered in a thin brass covering . As noted previously, paper shells used to be common, and are still made, as are solid brass shells . Some companies have produced what appear to be all - plastic shells, although in these there is a small metal ring cast into the rim of the shell to provide strength . Often the more powerful loads will use "high brass" shells, with the brass extended up further along the sides of the shell, while light loads will use "low brass" shells . The brass does not actually provide a significant amount of strength, but the difference in appearance provides shooters with a way to quickly differentiate between high and low powered ammunition . </P>

When did they stop making paper shotgun shells
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