The reason the Army adopted the Trapdoor Springfield was due to a few reasons many people don’t know or understand. The 1866 was well in service by 1876 and available for any testing the military did to determine the best all around rifle and cartridge for the cavalry.
It was determined that the 45-70 and the 45-55 for cavalry was more suitable for plains Indian warfare. It could be loaded and fired at a rate of 8-10 rounds a minute and the experienced trooper could get 15 or so per minute. In a skirmish line, this is an effective battle situation and the longer range of the Springfield gave the cavalry a great advantage.
The Army did try Winchester repeating rifles as well as Spencers and the single shot Springfield was adopted due to the range, firepower and reliability. Not only could the Springfield shoot farther, it was also capable of putting down a horse, which was another good reason for the larger bullet and load.
Myles Keogh’s horse, Comanche, sustained at least 7 small arms wounds and is credited to be the only Custer battle survivor. This again testifies to the advantage of the Springfield over the repeaters of the day.
Ever hear of the phrase "Don't put all your eggs in one basket"? The Trapdoor was far superior in firepower then the Repeaters. I personally have yet to yield that Custer lost due to firepower issues. From the Battlefield "Patterns" he was in almost a retreat the whole time once he got to the river. And once they got into the open range where they should have kept the Indians at bay with the Trapdoors. It would appear that they were simply overwhelmed by large Indian forces, whom kept them pinned down with Repeaters. If the repeaters were useless, then the Indians won with bows, arrows and knives....and then kept them pinned down at Reno's defense line with captured Trapdoors as well as their repeaters.
