I cant find much information on this subject. All i have found is one method of tapping the hole and inserting a screw into the hole and peening the end to hold it in. What are other methods used. I am replacing a barrel hook and want to learn other ways. The only other way i can think of is making a steel rivet and shape the end to catch the hole in the main spring barrel.Then Peen the end in the hole to hold it in.