Make sure you have a well fitting screwdriver & remove the one screw holding the sideplates on. There is a pin which goes through the cocking hook & both hammers with a key milled onto one side, the ends will be visable in the hammers after removing plates. If the bbl is lifting the hook but hammers aren't raising, sounds as if either the key is sheared or hammers missing.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra