Just picked up and disassembled my model 21 for the first time and it is quite an adventure. First off i don't think it has ever been cleaned properly in its life but fortunately all of the machining in the action is still crisp and looks undamaged.
The only thing that i find rather puzzling is the fact that there is a part missing. I don't have part 57M on the following picture:

There is nothing there at all; looks like i will have to track down and order one of these with its attached spring. In addition the safety leaf spring is broken and the spring on the recoil block (54m) is just gone.
The other odd/minor problems are that the end of the safety (the one with the attached leaf spring) looks to be broken short. I was thinking of welding some metal to the end, shaping it to the proper size then heat treating it to harden the metal a bit.
Does my plan sound solid or am i missing something? i will post pictures as soon as i can to help with the visuals.
I can't wait to get out to the range with this amazing beauty.