Here is the Martini Schuetzen rifle I bought from Mike. And it was a pleasure to meet and we had some good conversation.  It had been in a gun case since Mike’s grandfather brought it back from Germany.  Needless to say, it needed some Tender Loving Care:
**Remove the light surface rust (no pits) – used Eezox and brass wool
**Work the wood over with conditioner (Clenzoil works great on wood in addition to being a cleaner and lubricant)
**Clean all part
**Give the minty bore a long over due cleaning – Eezox, brass brush and cotton balls

The measurements:
0.354 – Bore , using ISSO certified plugs
0.360 – Chamber cast = 378 tapered to 375 and it is a 4 groove, not 5
0.595 – Rim Diameter … either the10.5x47R or the 10.8x47R Martini Target that matches close to the published 0.591 diameter.  What puzzles me is the stated bullet diameter is 0.441 which seems too large for the groove diameter.  CerroSafe casting to be done
30 9/16” – Barrel Length
0.575 – Inverted dove tail rail 
49 ½” - OAL 
Diopter:
Stud – 0.580 front and 0.635 back
Stud hole – 0.305 x 0.305
Barrel Markings: 
** M. Gruny JNGDLSTAT stamped and inlaid with silver wire 
Verticle marks from the muzzle to the breech:
** 3 dots -?
** Crown over capital B (left side) = Proof for Only Tested Once (Foreign Guns)
** Crown over capital U (left side) = 2nd Proof and Examination
** Crown over capital G (right side) = Proof for Rifles
**108.49 ... Rifle Gauge Table
The British proof law of 1868 had set up standard gauge sizes from .300" (172.28 gauge) to .450" (51.05 gauge) in .010" increments in the same sense that a shotgun bore is gauged, by the number of round lead balls of that diameter that make a pound. The Germans adopted this somewhat awkward system as well.
Gauge – inch
108.49 - .350 

** Serrated edged circle with a Gothic H in the center =  I don’t know .  A guess would be Hamerli?

Pictures in Part II - The New M. Gruny Martini Schuetzen Rifle

Gruny doesn't sound particularly Bavarian (or even German for that matter), but he obviously made very nice target rifles.

Back in the '70's when Biggi was a "kloins Maedl", we would stop at the Autobahn PX in Ingolstadt on our way back from deployments to the Iron Curtain, then we'd "race" back to Augsburg from there.

Biggi, thanks for looking at the post and as always Hugs & Kisses for passing on your knowledge to us folks trying to thread the needle about rifles we find over here.  Especially the town, the gunsmith's background and clarification about the crown marks. I looked through my Alte Scheibenwaffen book and there is almost no information in it about Martini actions or examples or gunsmiths except one Buchel

This rifle is going to be a tough one to get original sights and loaded rounds to be able to enjoy shooting it.
** The sights are going to be a long search unless I get lucky.  In the meantime, am going to scope it.
**  After I do the CerroSafe chamber cast today, I'll know better the caliber.  Then the hunt begins for existing cartridges or cases that I can reform after buying the full length sizing die ... either stock or custom made.  The proper bullet mold could be an issue too
Will be a fun project though bringing it back to life!

Frank - good observation - the 360 is wrong ... Chamber cast = 378 tapered to 375 and it is a 4 groove, not 5.  So the groove depth runs 024 to 021.

Oh, BTW ... the chamber cast shows the rifle is a 10.5x47R

Frank, the parent case is the 11mm Mauser ... 
source: CastPics > References = Cartridge Conversions ... (You need to Login or Register to view media files and links);

Would you believe there is every known Nominal Caliber - Cartridge - Parent with full reference records ... +1300 on this file?  A definite bookmark or download.

Best find so far for brass is Midway: 20 loaded 11MM  Mauser rounds for $58 

The trick now is to find plain brass for 43 Mauser, 11mm Mauser and 11.15x60R that are all the same.  Bertram is supposed to have the brass but they don't.  And neither does GAD Custom Cartridges 

CH4D has the die set for 10.5x47R.  Then a RN bullet mold with a 419 diameter base that weighs between 260 and 298grs is an additional search ... not to mention the diopter & fore sight 

Two days into the 'Fun Project' is just beginning but the plus is I have plenty of black powder!  With BP being a weak powder - slim chances blowing the rifle apart

Rocky Mountain Cartridge will make about anything you want in the way of brass. Can choose large or small primer pockets, as well. Could have Dave make up 5 of each and test before placing a larger order.

My progress for the day ...
* Gunauction.com
* 10.5x47R collector cartridge z484
* Auction Closed:      March 4, 2012 09:40:15 PDT    4 months too late
*            1 Bid(s) ($5.00 starting bid)

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(You need to Login or Register to view media files and links) ... Ideal 412263, 288gr (only if the mold was available) 

Frank, the chamber cast showed the grooves to be 378 tapered to 375 and it is a 4 groove.  I was wrong with my 1st post - that I corrected.

Cartridges of the World states the bullet diameter to be 419 and with a 378 groove, this sounds to be too big of a diameter.  The Ideal mold has the correct RN shape and the diameter is logical, so it is going to be my template