In my quest to collect as much brass as possible while in Europe, I came across an eGun ad for 20 pieces of 9.5X57 brass. It was a deal at the 11,50 euro I paid for it, so I grabbed it. I should have been paying attention.

In fact, the ad (and the product) was for 9.5X57 Mannlicher Schoenauer RIMMED brass. I saw the R there, and completely missed it. That's ok, I'll take the hit. But...

I can't find any information on any rimmed rifle. The only info I found was on this site: https://cartridgecollector.net/cartridge/95-x-57r-ms/, where the only comment is: "This is the rimmed version of the 9.5×57 MS and might have been a special order for a client. Cases were likely produced by Horneber"

The head stamp in the photo looks exactly like what I have, and it is definitely a rimmed cartridge. Does anyone know of any such beast? Double rifle? Something else?