I happened to catch a show on the History Channel the other day about a group of archaeologists doing a forensic reconstruction of Custer’s annihilation at the Little Bighorn. One of the things they determined (no surprise, really) is that the Indian forces were armed with a variety of weapons, including Spencer and Henry repeaters. The 7th Cavalry, of course, had Trapdoor Springfield carbines – just about the worst weapon I can imagine for a fast-moving cavalry unit.
Now, I will acknowledge right up front that I’m not nearly as well-educated on the American West as I should be…so if I get something wrong please let me know in the comments. I expect the choice of Springfield carbines for the cavalry was largely because the Army wanted them to have a weapon with enough stopping power to drop a horse (and because the Springfield was the standard infantry rifle and thus logistically convenient). There is some validity to that choice, but (IMO) not much. The problem is, how is a moving horseman supposed to actually make use of the range and power of that primary weapon? It’s only possible when he is dismounted, and effectively acting as infantry.
It seems to me that the technology, terrain, and conditions were ideal for the emergence of the medium (or short) range, highly mobile tactics that didn’t really become widely practiced until WWI trench raiding. In fact, I think it’s pretty likely that some groups of Indian warriors did in fact develp these tactics, while the US Army was administratively unable to. Basically, take a mounted fighter and equip him with a moderate-range, high-volume firearm like a Spencer or Henry and you give him the same advantage that a German with an StG44 had over a Russian with a Mosin-Nagant.
In fact, it gets more interesting the closer you look…consider that the Spencer and Henry both used short rimfire cases. Bigger than pistol rounds, but significantly smaller than the .45-70 standard rifle cartridge. One might call them “intermediate” size. Hmm. I wonder what might have changed if the Army had been flexible enough to recognize the potential of trading long-range stopping power for volume of fire?