Repeating rifles were beginning to be used, particularly by union cavalry, but for the most part the single-shot breechloader was the state of the technology for infantry weapons in 1861. And revolvers, of course, in the hands of a few.
And cannons. Lots of cannons, often loaded with grapeshot.
But like you said... all the Europeans at least had the opportunity to learn from the horror of our civil war, gatling guns or no.