My 1st Drilling - a Sempert & Krieghoff Blitz-Action - 16x16x8,57JR - 21-3/4" bbls

Although I've collected several Cape Guns over the years, I just purchased my first Drilling.

Its a - Sempert & Krieghoff Blitz-Action Drilling in 16ga,16ga, 8x57JR

I was drawn to this one because of the very short barrels, and its very good condition, with nice engraving. I've figured out the cocking and shooting sequence but have no idea as to the function of the little button ahead of the right trigger. Would like to know if anyone can help with information about this feature and the markings shown.

As always, comments are welcome.

[Linked Image from buckstix.com]

[Linked Image from buckstix.com]

here are links to the pictures for those hat cannot see the pictures in the post

http://www.buckstix.com/buckpics/krieghoff-11542-000.jpg

http://www.buckstix.com/buckpics/krieghoff-11542-proofs.jpg