Welcome here!

So this will be similar as on this rifle from Nowotny, Prague
http://forums.nitroexpress.com/showflat.php?Cat=0&Number=262207&an=0&page=0#Post262207

"H" will probably stand for Hirsch / Rothirsch / red deer, this is the "top-of-the-line-game" in German hunting.
"R" is probably Reh / roe deer.
The other initials will need some more thinking.

The crown in the silver oval shows the owner was from nobiliy. The design of the crown indicates his rank:
http://de.wikipedia.org/wiki/Rangkrone

Gründig was in Dresden.
Pictures will be most welcome.
Posting them should be easy. I use a german site, www.picr.de
All in german, so maybe not a good choice for you

fuhrmann