The photograph on the left is a picture of the 91/30 Russian sniper stock with the barreled receiver removed. At the time that this picture was taken I was in the process of refinishing a few Albanian SKS rifle stocks. In the background can be seen the cleaned and inspected barreled receiver assemblies of these SKS's waiting to be installed back into the refinished stocks.
The picture on the right is another 91/30 WWII era Russian sniper rifle that is in the collection. In this case though, it is considered an ex-sniper by many collectors including this author. In this picture we are looking inside the chamber. Notice how the holes for the scope mount screws have been filled in. On the other side, it is nearly impossible to see where the holes used to be. The holes are filled in and welded shut and then the receiver is reworked. The Russians removed a rifle out of sniper service for a variety of reasons including, a loss of accuracy, damage, not needed any more, and so on. To see some more pictures of this rifle please click HERE .
The Mosin Nagant rifle by Terence W. Lapin
Handbook of military rifle marks 1866-1950 by Richard Hoffman & Noel Schott
Official guide to gunmarks by Robert Balderson
The standard directory of proof marks by Gerhard Wirnsberger