seems to be a Mauser cartridge clone, I think Horneber in germany make the werder case. you can order this with huntington but will wait long time( 1 year?). you can rework 11,15x60R brass. there are many different versions of your case and I think this was only because chamber dimension where not standardize in this times.
you can allways rework a mauser die set. have do this two times , ones was also for a belgian cape gun:12/65 and 50/110 WCF. cut the top of a 50/70 resizing die for full length resizing. another was a full rifled 28 bore with 40mm long case. here i cut the bottom end of a 577 snider bullet seting die. dies are hardened so you cant make this with a saw but a grinding machine works for such simple things.
question is where the neck starts on your case you have to cut all dies on the bottom till the case chamber in your gun.

Thanks, PWM. Say, that must have been a lovely cape gun in 12 ga./.50/110!

yes it was, not my own but a friend in switzerland have had it, have only made all reloading stuff for him. the belgians have allways build interesting cape guns. see in novenmber a cape gun in 12 bore/ 38/55, no doubt this guns are made for the american market and yours was build for the german market.

I have inherited a Ferlach (Austria) hammer cape gun, rifle barrel is 11.15 x 51 R (or 11.2 x 52 R), 16/65 ga. shotgun barrel (steel barrels). And 16/16 Damascus shotgun barrels extra.
The cartridge is definitely based on the 11.15 x 60 R Mauser. Mauser cases can be reformed and fit perfectly.
I know of one more gun from Vienna which may be chambered for the same cartridge.
Many many years back (say late 70s) my father had a set of dies made custom made by RCBS - however I found those do not fit properly, the neck is sized too tight.
I will dig for case dimensions later.

A 11.15 (or 11.2) x 51 R Kropatschek-Heissig must have been reasonably popular in Austria, but it may have been based on an Austrian Werndl cartridge (different case head dimensions). I still have no clear answer if my rifle is "Kropatschek-Heissig" or not - anyway, from a practical view it does not matter.

I tried some loads (BP only), but had to stop due to some technical problems, and due to lack of time
Waiting for better times - less work, more fun.

Fuhrmann

yes I forget the Kropatschek-Heissig, this was very popular and loaded from Hirtenberger till WW 2. but I think its to long for this chamber and believe its bases on the 11,2 Mauser case and not on the M73 werndl.

pwm,

Dorfner in Vienna (http://www.waffen-dorfner.at/xmain.html#)loads the Kropatschek-Heissig, he said it is based on a Werndl cartridge (logic for an Austrian cartridge, not much love for the Prussians those days).

But another Austrian collector and reloader thought otherwise, but I have no details.

Fuhrmann

you may be wrong about what the love for the mauser rifle in austria was. from the mauser 71 on upwards allways are mauser rifles build in austria. the year 1866 was only an episode in history and austria was never a
foreign country like Switzerland is
Have never get a Kropatschek-Heissig cartridge but it looks me on old pictures to big for a werndl basic case. when you say the mauser have 13mm on the base and the werndl have 12,4mm thats not a great differenc well thats rigth. but when you look on the M73, a 11,5x50R Werndl it is a straigth case. it havn't a shoulder but the shoulder of the kropatschek round looks like the mauser cartridge.