TRAPDOOR EVOLUTION

he rifle designed by Connecticut gunsmith Erskine S. Allin (1809–79) and manufactured by the Springfield Armory in Massachusetts began as the cheapest means of converting Civil War muzzleloaders into a breech-loaders. Allin’s first effort, the .58-caliber rimfire Model 1865, featured a hinged breechblock soldered to the barrel. Problem was, when the barrel heated up, the block often fell off. Improvements included a hinged block in a receiver and a rifled liner in the barrel to accommodate a .50-caliber centerfire cartridge. Unfortunately, the liners had a habit of “starting” (i.e., creeping forward), and it was determined it would be cheaper to rifle