The Russian Mosin Nagant Forum

Hello everyone! I am writing an article about the Estonian War Museum and the Mosin examples on display there. When i was visiting the Museum i shot the following pictures of what appear to be an M91/30 (or a Dragoon) in relic conditions found inside a tree. What is really weird is what is attached to the hex receiver. What do you think it would be? Part of a diopter maybe? Thank you in advance ! Ric

Okay that's interesting, and I have no clue why it would have a diopter style sight on it.

Local partisan adaptation maybe.