America's first standard metallic cartridge for military rifles. Converted Civil War Springfield muskets into breech-loaders through the Allin trapdoor conversion.
Type: Rifle
Introduced: 1866, United States
Parent case: None
Standardization: SAAMI
Bullet diameter: 0.515" (13.08 mm)
Case length: 1.75" (44.45 mm)
Overall length: 2.25" (57.15 mm)
Max pressure: 22,000 PSI
Rim type: Rimmed
Primer: Large Rifle
Typical twist rate: 1:42
Muzzle velocity: 1200–1350 fps
Muzzle energy: 1440–1820 ft-lbs
Effective range: 400 yd
Common bullet weights: 450 gr
Primary use: Military (Historical)
Production status: Active
Also known as: .50-70 · .50 Government
History: Adopted in 1866 to rapidly convert the Army's enormous supply of Springfield muzzle-loaders using Erskine Allin's 'trapdoor' conversion. Served through the Indian Wars era until replaced by the .45-70 in 1873. The concept of converting existing stocks rather than buying new rifles was driven by post-Civil War austerity.
Notable firearms: Springfield Model 1866 Trapdoor, Springfield Model 1868
Military use: {"country":"U.S. Army","years":"1866-1873"}
Similar cartridges: .45-70 Government, .50-90 Sharps