I wanted to let everyone know that I tried the process suggested by xausa above and it works perfectly.
I still don't have a snap cap but being impatient to find out, I placed a dowel rod in my vise and held the rifle part of the breech face against it while I held the cocking slide forward and pulled the trigger then slid the cocking slide to the rear. It works like a charm. The rifle barrel does not fire and the tumbler and pop-up sight are returned to the uncocked position.
As suggested, if I were uncocking the rifle barrel with a live round in the chamber, I would break the gun open first.
Eventually I will post pictures of the gun on the GGCA forum as I don't know how to do that here.
Regards,
Roger
