This is the Loading gate screw also called spring cover screw Winchester 1873. This unique screw has an OVAL head and is designed to fit rifles with serial numbers prior to 90,000. On these rifles the Loading gate (spring cover) was attached to the side plate from the outside of the rifle. (After serial number 90,000 Winchester switched to a screw --part number 71f-- that has a flat head and attached the Loading gate (spring cover) from the inside of the side plate. 1876 Winchester rifle this screw was used along with the flat head Loading gate (spring cover) screw (71f) but the oval head screw was screwed in from outside of sideplate.
