Teddy Roosevelt’s guys had .30 Krag carbines. The other volunteer regiments had the 45/70 Springfield. The regulars had Krags.
My great-grampa carried a 7mm Spanish Mauser because he was a Spanish soldier.
***The other volunteer regiments had the 45/70 Springfield.***
IF I remember my history, Congress continued the use of the black powder 45-70 into the smokless era because there was so much ammo that need be shot up!