J.P. Lindsay was a former Springfield Armory employee when he designed and patented an idea for a two-shot, shingle-barrel pistol. The apocryphal story is that Lindsay's brother was killed in a firefight against two Indians, while reloading his single-shot rifle - so Lindsay was moved to design a weapon which would have saved his brother.
The idea is a simple one, and Lindsay is not the first to have made such a gun. The single barrel has two flash holes, situated such that two stacked charges of powder and ball may be loaded and then fired one after the other. The pistol has two hammers and uses two percussion caps. Unlike the Walch revolver, Lindsay used a single trigger, which would fire first the right hammer if both were cocked, and the left hammer is only it was cocked.
The "Young American" (Lindsay's trade name for the pistol) was made in pocket, belt, and martial sizes, with this one being a martial type in .45 caliber and with an 8 inch barrel. Only about 100 of these were made, as the concept has substantial practical problems - namely the many ways that one could wind up firing the rear charge first.
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