Allin Conversion

About the Allin Conversion

The Allin Conversion is a single-shot, breech-loading rifle developed at the U.S. Springfield Armory by Master Armorer Erskine S. Allin. Officially the Springfield Model 1866 (the Second Allin Conversion), it was created by milling out the breech of surplus Civil War muzzle-loading rifle-muskets and fitting a hinged 'trapdoor' breechblock, converting them to fire the metallic centerfire .50-70 Government cartridge. The design gave U.S. troops a rapid, reliable breechloader and established the trapdoor mechanism that would define American service rifles into the 1870s and 1880s.

Erskine S. Allin's conversion was prized as 'pure Yankee ingenuity', a cheap way to turn a mountain of obsolete Civil War muzzleloaders into modern breechloaders. At the 1867 Wagon Box Fight, soldiers armed with the new .50-70 trapdoors held off a far larger Sioux and Cheyenne force whose warriors expected the slow reload of muzzleloaders.

Allin Conversion specifications

The 1866 'Second Allin Conversion' chambered the .50-70 Government cartridge, replacing the ineffective .58 rimfire of the earlier 1865 'First Allin Conversion'. It proved decisive at the Wagon Box Fight and Hayfield Fight (1867) along the Bozeman Trail.