I think what you are looking for is the changes done by King & Hayes. It is patent # 973655 on 25 Oct 1910. You can read this patent if you want, just go to the
www.parkerguns.org page and click on the Technical Information link in the list on the left side of that page. There is a link at the top of the Tech page for gun related patents and it will take you to a list of patents where a link can be found for patent 973655.
Hope this helps!