l heard that Butler bought a few. I have no recollection if he ever used them.
With Custer at LBH, and he left them behind, I don't see how they would have made much difference.
On a related note, how much were gatling guns used during the Civil War. I vaguely remember hearing that they were developed during the war but did not see much use. Some one told me recently that they were used by the Union, but they stopped using it because it was "unfair"?
Custer should have taken them with him on the Rosebud.