Springfield Model 1865 Allin Conversion

About the Springfield Model 1865 Allin Conversion

The Springfield Model 1865 Allin Conversion is a single-shot, breech-loading rifle developed at the U.S. Springfield Armory by Master Armorer Erskine S. Allin. As the first of the 'Allin conversions', it was created by milling open the breech of surplus Civil War .58-caliber muzzle-loading rifle-muskets and fitting a hinged 'trapdoor' breechblock that swung upward to chamber a metallic .58 rimfire cartridge. A long firing pin running through the breechblock was struck by the rifle's original percussion-musket hammer. It established the trapdoor breech mechanism that would define American service rifles for the next two decades, though its underpowered rimfire cartridge and complex extractor led the Army to redesign it as the .50-70 Model 1866 within a year.

Faced with a million-plus obsolete muzzle-loading rifle-muskets left over from the Civil War, Master Armorer Erskine Allin devised a thrifty 'Yankee' fix: cut open the breech of an existing musket, hinge on a trapdoor, and turn a slow muzzleloader into a breechloader. The 1865 'First Allin' was the prototype of that idea, but its weak .58 rimfire round persuaded the Army to swiftly rework it into the harder-hitting .50-70 of 1866.

Springfield Model 1865 Allin Conversion specifications

About 5,000 Civil War rifled muskets were converted to the Model 1865 'First Allin' pattern, chambered for the ineffective .58 rimfire cartridge. The design's shortcomings led directly to the rechambered .50-70 'Second Allin' Model 1866. Allin received U.S. Patent No. 49,959 for the conversion on September 19, 1865.