The centerfire cartridge was invented by one Monsieur Clement Pottet of Paris and improvements were made by Monsieur Francois E. Schneider, also of Paris. The centerfire cartridge was introduced to England in 1861 by Mr. George H. Daw who owned a rifle manufacturing company and bought the English patent rights from Monsieur Schneider. The centerfire didn't get patented in the US until 1866.
All that was readily available were Henry Rifle cartridges in the US.
America was engulfed in the searing flames of the Civil War, and the first Henry rifles were in the hands of Union soldiers by mid 1862. Due to its revolutionary design and rapid rate of fire, the Henry quickly found popularity both with the military and civilian purchasers. Early sales were especially brisk in Kentucky, Illinois, Missouri and Indiana. With its reliable .44 caliber rimfire metallic cartridge, the Henry produced a rapid and highly accurate fire.