The Colt .45 (Peacemaker) came out in 1873 as the Cold Army Model with 7-1/2” barrel. It was accepted by the military as the officer/cavalry side-arm. The 7th Cavalry carried them at the Little Big Horn. It also came in .44-40.
Their long arm was the 1873 ‘Trapdoor’ Springfield in .45-70. It came in both rifle (infantry) and carbine (cavalry) models.
Both Remington and Smith & Wesson had competing models. The various S&W model 3 came in various configurations including the Russian, the Schofield and the American. And Remington had its 1875 model.
I have a Winchester 1886 in .40-82 hanging on my office wall behind me. It shipped from the factory in 1895. That’s a heavier frame model with heavier octagon barrel. The 1886 was marketed for big game.
All true, but that was the Army, and they had the latest equipment. Your average “Westerner” in the 1870s ould have carried a Remington or Colt conversion. Colt made thousands of conversion models in the early 1870s.
I have a Model 1873 Winchester in .44-40 hanging on my wall, but the Henry Rifle and Model 1866 Winchester (like the guy in the Yale picture in the post above is holding) were more common in the 1870s.