Here it is. I'm to pooped to look in Toms book. Thinking this one is for Zimmetstutzen. Same thing just smaller.

They were made to be disassembled & reassembled on the kitchen table with no tools.  It's like a challenging jigsaw puzzle.  The pieces have to go back in a certain order.  

My Haenel Aydt has a chamber that allows almost any .30-30 or .32 Special case to be used.  Rim diameter does not matter.  Case length may not be critical unless you use stop-ring bullets, maybe not even then.

I'm relatively sure that you can breech-seat bullets with a plugged case.  If not, you might be able to use fixed ammunition with a longer than 46 mm case.  Experiment, but keep pressures & velocities low.  It's not a High Wall.

I think 8.15 Brass is available from Huntingtons. The Germans don't use breech seaters, fixed ammo only. I have a Buchel Ideal and was trying breech seating and was getting a "modified choke" group. I went to fixed ammo and success! 1 1/2-2" at 100 with iron sights. The "Original" on the side of the breech block means that the action was made by Haenel but the rest of the rifle was made by another firm, probably in Zella Mehlis. The numbers on the top of the barrel, I believe, are for different ranges. Some clubs didn't have a 300m range. Most shooting in Germany now is at 100m. I never saw any shooters using stop ring bullets.

It is my understanding that the open barrel sight is the intended sight to use in matches.  The  rear appature sight is only to  sharpen the barrel sight.

Early on a three sight system was used but soon discarded. The diopter (Peep) sight is used for the Stand match. In the old days Stand match was at 200 meters, now 100m. Attended a few matches in Germany (someone had to drink the beer) and all shooters I talked to used a new design swaged bullet, no grooves, with a special lubricant. All used fixed ammo and most were using bullets I thought were oversize. Contact Biggi for the final word.

Per my sources with the German Gun Collectors Association...

Contrary to most U.S. target shooters who are accustomed to shooting for accuracy with large diameter tang sights -- the German shooters used the barrel-mounted "mid sight" to sight on the target; that was THE sight used for accuracy.

As .22-5-40 said above, the only reason a large diameter rear peep sight was used was to sharpen the image (per the aperture effect) of the mid sight.

All German target rifles I have had, luckily (or so I thought...) had the U.S.-desirable large diameter & adjustable tang sights and front sights -- but none have ever had a 3rd, or mid sight, present.  (And if they did -- I'd bet I would have removed it anyway!)  The markings on that flat you showed are likely used to slide the mid sight fore and back, based on light conditions, or for different shooters.

Oh, and some German GI-bring-back target rifles are sold with "no sights" (or "missing" sights, that is), as that made it easier for returning GIs to "bring back" an incomplete rifle.

Hope this helps.

Old No7