On the .45-70 not working for Custer at Little Big Horn, it is true Custer got his a** waxed but this was not entirely the fault of the .45-70. The ammunition supplied the 7th Cav was copper cased rather than the specified brass case the Trapdoor Springfield was designed to use. The copper cases were prone to the extractor tearing the case rim rather than extracting the shell. The troopers then had to extract the shell with a knife to reload. Again, this alone did not seal their fate. Little Big Horn was a combination of many things not the least of which was G.A. Custer's underestimation of his enemy and his overconfidence in his abilities. The best analysis's of Little Big Horn that I have read indicate that CPT Tom Custer's Troop was the only group to lay down their mounts in a defensive perimeter and make a good fight of it. These analysis's indicate the rest of the 7th made a running fight for high ground but were overwhelmed by very superior numbers. The much maligned Maj. Reno lead his men in a running fight to the high ground occupied by the 7th's Trains commanded by CPT Benteen. Reno & Beteen ordered thier men to dig in and fight. They held out until relieved by GEN Crook. As to the Battle of San Juan Hill, I wonder how a .45-70 bolt-action would have fared against the Spanish Mausers? To compare single shot trapdoor actions against magazine fed bolt-actions and say the caliber is the problem is not a good analysis of the situation. I would also point out that the US Army & Navy began adopting magazine fed smaller caliber bolt-action rifles with the 1892 Krag in .30-40. This was 6 years before San Juan Hill. Our esteemed politicians and the ossified military leadership just did not push for the rapid fielding of the Krag rifle.
The US Military has a long and inglorious history of choosing weapons and ammunition through political manipulation and expeditious supply chain choices. Many if not most of the time the wants and needs of the front line troops are 2nd or 3rd considerations of choice.
PS The .45-70 Trapdoor Springfield Rifle remained as a limited standard US Military rifle until the adoption of the US Rifle M1 Grand in 1937. Many of the state militias were still armed with the .45-70 until then. As far as I know, no active troops used the .45-70 after the Spanish American War.
Benteen & Reno were not relieved by General Crook; Crook's men had been turned back weeks before by the same Plains Indians at the Battle of the Rosebud. Benteen & Reno were relieved by the Terry/Gibbon column (General Alfred Terry, cmdr of the expedition) when they arrived on the 27th of June.
The "much maligned" Major Reno
deserved much maligning; he made a mess of the attack on the southern Indian village. Custer's Indian Scout Bloody Knife was with him, and when he had his brains blown out by an enemy gun, they splattered across Reno's face. Repulsed and alarmed, Reno called for a hasty and completly disorderly retreat back across the Little Bighorn River. This greatly surprised the Indians, who were themselves about to break from their hastily assumed positions (this from historians' interviews with the Indians who participated in the battle a few years after the fact).
Benteen was not much better. Handed a written out order by a trooper in Custer's detachment to bring packs and quickly (meaning "AMMO!") Benteen ignored the order and took position along with Reno.
The remarks about the copper .45-70 were accurate; Custer & his officers supplied their own ammo as they well knew its problems. As to Custer's over estimation of his abilities and underestimation of his enemies; to an extent, yes. But keep in mind several factors.
Custer had always been on the short end of things numerically; in every battle he entered into he had faced and defeated a superior number of enemy, be they Confederate soldiers or Plains Indians, and he had won in every battle. The tactic of hitting a sitting Indian village had been adopted because the army had realized that
it worked. In the field the Plains Indians were terrific soldiers with very effective and deadly strategies.
At the Battle of the Little Bighorn reality got turned on its head. Sitting Bull had prophesized about "bluecoats falling into camp" -- meaning their camp would be attacked, but the Indians would win. This gave the warriors the psychological boost they needed, while Custer and his 7th Cavalry were exhausted by a forced march.
Many other mistakes contributed to the inglorious defeat, not all Custer's. General Terry made some truly assinine decisions as well.
What might have saved the Seventh?
Tommy Guns.
M-16s.
B.A.R.s
M1 Garands
Phased Plasma rifles in the 40 megawatt range.
"Dust off and nuke 'em from orbit; it's the only way to be sure."
Or--- better yet, let history be what it is. It's more fun that way....