Heernen rifle chambering

[Orange fedora]

I purchased a lovely little Nagel & Menz Heeren. The chambering is unfortunately not clearly indicated. The proofs show 7.9 mm over 57 with a date code that indicates October of 1923. Is this enough to determine what ammunition should be used or will I need the chamber cast?

[mike ford]

Orange fedora,
I don't believe you will necessarily have to make a chamber cast, it will be helpful to "slug" the barrel, however. First determine if the rifle is intended for a rimmed or rimless cartridge. If the chamber and extractor have a rim recess, it is for a rimmed cartridge. If the extractor has a small pin with a spring behind it, set perpendicular to the chamber; it is for a rimless cartridge. It is more likely that it will be a rimmed cartridge. If a 30-06 headsize cartridge just fits into the chamber, head first, then it is either 8x57 IR or 8x57 IRS. If slugging the barrel shows a groove diameter of about .318" , it is 8x57 IR. If the groove diameter is about .323", then it is 8x57 IRS. If a 30-06 head will clearly not fit into the chamber( past the rim recess) and the groove diameter is about .318", then it is 8x57R/360. Smart money is on it being 8x57 IR, but it still may accept 8x57 IRS ammo. If a cartridge fired is an 8x57 IR rifle and the fired/unsized case will easily accept a .323" bullet, then you can use 8x57 IRS ammo even with a groove diameter less than that, but only if you decide to do so and the rifle is in good shape. If it happens to be for a rimless cartridge, it is either for 8x57 I or 8x57 IS. The test is the same as for the rimmed cartridges, just eliminate the "R". There is no rimless version of the 8x57R/360. Are we confused yet?
Mike

[Leatherman]

If you bought the gun at Timonium last weekend I know the gun and the guy you bought it from. He should have been able to tell you what he used in the gun. If you didn't ask him there, I can find out for you or give you his phone number. He is right down the road from me and we talk almost every week. Let me know if you need his number

[Orange fedora]

No, I purchased it about a month ago in an auction.

[chapmen]

Let us see pics from the rifle!!!!!!

[Orange fedora]

The rifle appears to be 8x57IR
I apologize for the poor picture quality, my camera's battery is dead and I'm having to rely on my phone.
IMG_20190329_120037.jpg
IMG_20190329_120013.jpg

[chapmen]

Is the barrel rib or the system signed by Nagel&Menz?

[Orange fedora]

Nagel&Menz is marked on one of the barrel flats near the scope