.45-70
The .45-70 rifle cartridge, also known as .45-70 Government, was developed at the U.S. Army's Springfield Armory for use in the Springfield Model 1873, which is known to collectors as the "Trapdoor Springfield". The new cartridge was a replacement for the stop-gap .50-70 Government cartridge which had been adopted in 1866, one year after the end of the American Civil War.
Nomenclature
The new cartridge was completely identified as the .45-70-405, but was also referred to as the ".45 Government" cartridge in commercial catalogs. The nomenclature of the time was based on three properties of the cartridge:
.45: nominal diameter of bullet, measured in decimal inches, i.e., 0.458 inches (11.63 mm);
70: weight of black powder, measured in grains, i.e., 70 grains (4.56 g);
405: weight of lead bullet, measured in grains, i.e., 405 grains (26.2 g).
The minimum acceptable accuracy of the .45-70 from the 1873 Springfield was approximately 4 inches (100 mm) at 100 yards (91 m), however, the heavy, slow-moving bullet had a "rainbow" trajectory, the bullet dropping multiple yards (meters) at ranges greater than a few hundred yards (meters). A skilled shooter, firing at known range, could consistently hit targets that were 6 × 6 feet (1.8 m) at 600 yards (550 m)—the Army standard target. It was a skill valuable mainly in mass or volley fire, since accurate aimed fire on a man-sized target was effective only to about 300 yards (270 m).