The big thing during the US Civil War, rifle-wise, was still the muzzle loaded rifled musket. The Springfield versions were later converted to breech loaders (Trapdoor Springfield). Some repeaters, like the Henry, were also used.
To the best of my knowledge, bolt actions were not used in the US Civil War.
The first bolt action was invented in 1829, but generally languished until Peter Paul Mauser, in 1860, came up with his design that was eventually developed into the Model 98.
Are you sure that is a true bolt that seals off a chamber (images not at all clear) or is it a cover for a nipple + percussion cap setup? Like a modern inline ignition muzzle loader?

Yep, that's a muzzle loader, the bolt just acts as a cocking mechanism and allows access to the priming nipple.
To the best of my knowledge, bolt actions were not used in the US Civil War.
The first bolt action was invented in 1829, but generally languished until Peter Paul Mauser, in 1860, came up with his design that was eventually developed into the Model 98.
Are you sure that is a true bolt that seals off a chamber (images not at all clear) or is it a cover for a nipple + percussion cap setup? Like a modern inline ignition muzzle loader?

Yep, that's a muzzle loader, the bolt just acts as a cocking mechanism and allows access to the priming nipple.
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