I am in the process of emptying out my safe and was considering parting with my K31 since I don't get around to shooting it. The rifle itself is in very good shape, I purchased it in 05 from AIM. The value comes from the Diopter I purchased from the Wyss Waffen store during a trip to Switzerland. I am having a hard time finding any information (in English). Here are links to the 3 parts I have.