I believe that the Russians were the first imperial power to employ the Gatling gun, in Central Asia and the Far East.
The British, I think? I have it that while the UK acquired Gatlings by 1871, their first use was at Ulundi against the Zulu in 1879, after the stinging defeat at Isandlwana, and two years after the Great Strike of 1877 in the U.S. railroad sector.