As stated, a Model 3 Russian, 2nd Model or Old Model 3 Russian. The stocks just do not look right and may not be original. The stamping "Russian Model" indicates that the revolver was made for the commercial market, not Russia. Problem is that Roy Jinks book states that the commercial guns were made in serial number range 32,800 to 39,000. Another batch from 1 to 9,000 were stamped "Reissue July 25, 1871". This is a large and heavy revolver, with a frame large enough to make it difficult to cock the hammer when shot with one hand. Several were cut at the factory for a shoulder stock and cut twice on the backstrap and once on the butt so looks like factory work.
2nd Model has a short chamber that makes it impossible to chamber standard 44 Winchester, plus the chamber would have two step-down rings. Check closely and let us know what you see in the chambers.
Lastly, there were three different 44 Russian Models. The First Model which was the same as the Model 3 American, the 2nd Model which had the long ejector rod housing, and the 3rd Model which had a shortener barrel and ejector rod housing. The picture shows a 3rd Model on top, a 2nd Model in the middle and a 1st Model at the bottom.