Help identifying uniforms circa 1917 revolution

[Dave]

Hello,

I have attempted to find out what I could about this picture on my own, with extremely limited success. This is a scan of a picture of my Grandfather (pictured sitting on the left side in the white tunic). All I am sure of is he was in the Tsar's army, and this picture was taken just prior to the Bolshevik revolution I am told. Who can tell me anything about what is in this picture? What are the ranks of those pictured, type of military unit, etc...

Any insight would be greatly appreciated.

[Gustaf B]

These men are from a mounted unite, from the chin straps on their caps, and the swords which appear to be the standard Cavalry Shashka. Your grandfather is Other ranks (referred to as enlisted in the US) and the fellow seated next to him is a junior Sargent (two cross stripes on his shoulder board) and the fellow on the far right is a corporal (one cross stripe on his shoulder board) This photo would have been taken before the revolution, as the shoulder boards were removed from the uniform, and rank was abolished by the Bolsheviks (until they realized that would not work). An interesting thing is the fellow in the back with the wrist watch.
Best
Gus

[Dave]

Gustaf,

Thank you for the information. That is very interesting about the removal of the shoulder boards after the revolution. Could any more be said of the type of mounted unit?

[Gustaf B]

I can not add any thing other than it could be an artillery unit, the wrist watch would be the only clue for that, and it is a stretch. There is nothing else that I can see to be more spacific, but some one else might be able to add something or correct me.
Best
Gsu