Those changes didn't take place all at once, and the factory didn't always keep a record of when they were made. Even the Winchester books can usually only approximate the changeover time. Further, changes were phased in, as parts were used up. They didn't just decide on July 15, 1922 at 3:35 PM to stop work, throw away all the old parts and start from scratch.
Further, many differences (like sights) were not changes, but factory options which were available over a long period of time at the customer's request.
Good luck in trying to date those changes, but you might not be able to do so.
Jim
|