With all due respect to Reldor, I believe what he has is a Third Model Russian as the ship date is three years prior to NM#3 production.
The 3rd Model Russian was made from 1874 - 1879.
How is the barrel marked? Is the front sight forged to the barrel instead of pinned? Does it have a large thumb screw in the top strap to release the cylinder fro the barrel assembly? These are all indicators.