7.7mm rimmed german sporting round?

[NoZombies]

I've picked up an old drilling, made by Thieme & Schlegelmilch in Suhl, and the 16 ga is no problem for me, but the 7.7mm (marked so) is giving my fits figuring it out.

It is NOT a .303 brit, as I thought before I started looking closer, but rather a straight taper case (as close as I can tell from looking at the chamber with my eyes) I'm not at the shop, and don't have any of my measuring tools handy for a few days.

Anyone have any knowledge of this round?

I suspect I'll do a chamber cast this coming week, although shooting the gun is a long ways off. I need to do a lot of work to get it up and running again, but it should be a fun project, I've wanted a drilling for a while.

[NoZombies]

Well, the 7.7 is the proof mark, probably indicating the bore, rather than groove dimension. and after a little more research, I suspect that this is chambered for 8.15 x 46R

The chamber cast will tell for sure... and then to slugging the barrel...

[madsenshooter]

There was a 7x72 used in combination guns. There's nothing in Cartridges of the World under European Sporting Cartridges that utilizes the .303 bore (7.7MM), nor is there any straight tapered cases listing in British Cartridge section. You say you've some work to do on it, could part of the identification be missing? I guess we'll have to wait for your measurements, or someone with a bit more knowledge than Frank Barnes and I.

Ah well I was going to suggest the possibility of a .316 bore and the 8mm cartridges, but I see you're up late answering you own questions. Bedtime for Bob-o! Night!

[Larry Gibson]

I'm working on a similar drilling. The barrel is marked 7.7x57 but that is a misnomer as when these were made the Treaty of Versialle (SP?) prohibited any cartridges of 8mm. I have made a chamber cast and slugged the bore. The cartridge the drilling I am working on is for the 8x57R 460. The bore/groove diameter is .318 (the older original "8mm"). Google C.I.P drawings of cartridges and specifications. Make a chamber cast of your chamber and compare realizing the cartridge dimensions will be slightly smaller than the chamber dimensions. There are numerous rimmed cartridges made for drillings back then, particularly in the Suhl district/area. Most were actually 8mm(.318) and if made after WWII were misnamed to avoid the treaty violations.

Larrry Gibson

[NoZombies]

Thanks guys!

This one seems to date from between the wars as close as I can tell. I'll do the chamber cast this week if I get time, and see what it turns out to be. I'm still suspecting the 8.15 x 46R, but we'll see.

The gun was beautifully made, and then at some point, horribly neglected. At least the mechanicals and bores are good. I need a stock, and a lot of refinish work to bring this one back. I've gotta make claw mount rings as well.

I may start another thread if I can get a photo of it, but the rifle barrel has a very interesting, I assume some kind of patent, rifling pattern, with 4 equal width lands and grooves, but with an extra groove in the middle of each land that is about half the depth, and 1/3 the width of the land.

[KCSO]

Slug the bore and do a chamber cast and measure your results. I just did on like this and it had a 323 bore and a 32-40 reamer and it was a super nice 32-40 drilling. Just a thought.