 In the late 1860s and early 1870s, many army units continued to use outdated rifled muskets and other weapons like the Spencer and Sharps .52 caliber percussion rifle.The army wanted to standardize weapons and ammunition, and forced these units to switch to trapdoor Springfields once the Model 1868 went into full production.A Model 1868 Carbine version was experimented with, but never went beyond the prototyping stage.