Where many bolt action rifles used during the war ? I read that the Greene rifle was used at Antietam. It's said to be the first action seen by bolt action in warfare.
https://guns.fandom.com/wiki/Greene_rifle
Jhann Nicolaus Dreyser's needle gun was used in limited numbers in 1848 against danish government forces.
(one was found after a battle at Dybbøl that year)
But It was most likely in the hands of volunteers in the Schleswig-Holstein "rebel" army. So likely weapons in private ownership before the war. But used by men in official (volunteer) military units under the command of recognized officers.
But I don't know when the first bolt action was used, and I guess it also depend on the exact definition of a boltaction... But this is the first I know of.
Also during the rebellions across "Germany" in 48 some was looted from army arsenals and used against Government forces.
In 1849 some was issued to Prussian soldiers for some field testing against the danes. (don't know the number, but my guess would be less than 100)
In 1850 Prussia was no longer involved, so both sides was back to using muskets and rifle muskets.
(Yes, by 1850 the rifle musket was in use in combat in Europe despite the myth you can read in some books about the minierifle being the first in the Crimean war or even that this was first done during the civil war)
By 1859/60 the Prussians had finished rearming all their infantry with them. So The entire Prussian infantry force deployed against Denmark in 1864 had breech loaded rifles. (Their pioneers had muzzleloaded rifles)
Sure a army of 50.000 infantry* was rather small, compered to civil war armies, but that is still 50.000 breach loaders in one place. Something Iam not sure happened during the civil war? (that is just the size of the force used in Denmark, not the size of the entire Prussian army)
The first real big use was in 1866 during the war with Austria. (big as in 250.000+ in use)
And the first big war where both side used breechloaded rifles as the main firearm for its frontline infantry was the franco-prussian war in 1870-71