Unfortunately I packed away my books that are relevant to the Gatling Gun. Anyway, the .45-70 was predominantly carried by the volunteer units (as opposed to the Regulars) of the U.S. Army. Since the Army converted to .30-40 Krag, it stands to reason that their guns would be up to date.
What a confusing time it was for ammunition and it was almost as bad as the Civil War. Besides the 30-40 Krag, there was also the 6mm Lee that was carried by the Marine Corps and the U.S. Navy.
Vigilantibus et non dormientibus jura subveniunt. Molon Labe!