Just to really stir the pot. The U.S. Chief of Ordnance at the beginning of the Civil War was a man named Ripley, who has taken a lot of heat (then and now) for not adopting every cockamamie repeating rifle that came along. Most of that criticism is based, of course, on 20-20 hindsight. In fact, guns like the Henry were fragile and difficult to maintain in the field; the Spencer was better, but both required proprietary cartridges that would turn out to be difficult to supply. Not to mention the dozen or so other special cartridges used in the hodgepodge of carbines and rifles thrown into combat without a proper supply system.
Ripley was not against new ideas; but his view was that muskets of the standard caliber, for which cartridges could be provided, were better than "super guns" with no ammunition. And one point is often overlooked; Ripley, and other U.S. officers, knew the capabilities of southern industry and knew well that the C.S. would have nothng better. And they were right; the South had an adequate supply of rifles, mainly of the Enfield which was their standard rifle, but they never had anything better. They never were able to produce fixed ammunition; captured Spencers and Henrys were discarded when captured ammunition was used up. Other carbines were closed or welded up and used as muzzle loaders.
Once the war was over, and a new rifle was in the works, the view was that a powerful rifle, capable of use at long range, would be superior to short range carbines. It is basically the same argument heard in WWII and today. Which would be better in combat - an M1/M14 or a Thompson SMG?