Some years ago, I purchased a Mark 1*** rifle and the backsight slide was missing with the small screw. I was able to make a backsighr slide after a few attempts with help from a small milling attachment on my lathe. The bone inserts were made from hard wood and checkered. After this photo was taken, I went back and reduced the sharp checkering. Behind the inserts are two small diameter coil springs and I was only able to locate chrome plated springs of the correct diameter - which worked out.

My other photo shows the difference between the early and later backsight leaf springAttachment 83899Attachment 83900