Springfield Model 1866

The Springfield Model 1866 was the second version of the Erskine S. Allin trapdoor breech-loading conversion, originally devised as a way to convert rifled muskets into breechloaders and later forming the basis of the definitive Springfield Model 1873, the first breech-loading rifle the United States War Department adopted for full manufacture and issue to American troops. The Model 1866 corrected problems in the earlier Springfield Model 1865, most notably its extractor, and introduced a stronger .50 caliber centerfire cartridge in place of the weaker .58 caliber rimfire round the Model 1865 had used. Roughly 52,000 .58 caliber Model 1863 rifled muskets were converted at Springfield Armory for the new rifle, about half of which were shipped to Europe for use in the Franco-Prussian War, and the rifle itself was issued to American troops beginning in 1867. It played a major role in the Wagon Box Fight and the Hayfield Fight along the Bozeman Trail that year, where its rapid rate of fire disrupted the tactics of Sioux and Cheyenne forces who had faced only muzzle-loading rifles a few months earlier at the Fetterman massacre. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/