Thanks Rainey, but several question remain :
What are "clock-hand indicators?
What does DRGM mean/stand for?
" " 207 M " " ?
What do you mean by "disk set strikers"?
Is this a Prussian gun?
IS IT SAFE TO FIRE MODERN (SMOKELESS) AMMO IN IT (critical)?

Obviously, I'm unschooled in "doublebarrelspeak". I appreciate your patience.

Bo