I recently bought a Mark III. I am having the darnedest time disammbling and reassemnbling it. I have thye manual and have tried to follow it. When I got it disassembled and ready to assemble, everytime I got the bolt stop back in and tried to close the mainspring housing, the bolt stop would back out. I tried to disassemble it and see what was wrong and now I can't remove the bolt. It pulls out just about a 1/2 inch. Can anyone help?