To the best of my knowledge all H grade Lefevers were built on the Single large cocking hook type. Open the bbl & look to see if the cocking hook is being lifted. It should fit up in a groove in the bbl lug & is lifted by a pin through it, which is the one mentioned by Jim as the most probable cause. If it is missing you will see a small hole through the lug, or posibably the center is sheared off. In either case, the bbls will need to be removed, the cocking hook carefully pried up to cock the gun before a new pin can be inserted. Any competent gunsmith or machinist should be able to fit a new pin from drill rod.
