German 7.9x42.5mm perhaps for Rheinmental-Borsig Rifle

There is a previous thread titled “Unknown Rifle Cartridge”. Fede was extremely helpful, as always, in identifying this round. Now I would like to continue this discussion focusing on this cartridge and the candidate rifles.

My original post was:

"I have had this round for over 15 years. I just ignored it since the jar it came in was full of very interesting rounds from an interesting source, and this looked like a corroded bit of junk. Today I was digging around in the box picking out a set of items for ECRA, and decided to take some steel wool to the headstamps and had a real surprise. The headstamp is WWI German!


And the case is copper plated steel.

This made no sense since the dimensions are all wrong for a 7.9x57mm Mauser

overall length: 61.7mm
Case length:: 42.5mm
bullet dia: 8.17mm
head dia: 11.91mm
weight: 273.5gr
One side of the case has some deformation as shown like it may have been resized. I would consider it someone’s dingbat except it came to me directly from an individual who had held important arms and arms positions in the US Army during WWII and after the war worked for other government activities. He is mentioned by name in HWS, Vol III and I am sure Frank Hackley would recognize his name. His government work also resulted on a close relationship with the White Lab He was not a collector nor a tinker. He gave me his “Reference Box” which contained this round. I wonder if it was made by a friend as a joke, but I don’t believe he was the kind of guy who would have kept it in his Reference Box.

I suspect it still belongs in a junk box, but would appreciate opinions!


Fede than supplied the two following posts offering a possible identification of the item:

"Lew, certainly not a dingbat! Examples of this cartridge with different headstamps were found at the Krieghoff factory in 1945 and it is believed that they could be for the Gewehr 28 (System Heinemann) rifle developed by Rheinmental-Borsig. Known examples seem to be dummies or concept cartridges, because none was found loaded. Other examples surfaced years ago in an European collection, including a 7.9x35 also made from a 7.9x57 case.

Great junk box find, congratulations!




"John, I don’t know why the cartridge looks like this, but there is a note about the origin at the Woodin Lab. I assume that it was found by Col. Jarrett and later passed to Bill, but I don’t have more information.

It is also documented that the Rheinmetall rifle was designed for a 7.9x42.5 cartridge, among other calibers. The US tested this rifle in .276 Pedersen.

As Lew mentioned above, it looks like junk, but in this case the source is everything.



JPeelen also offered:

“To reform a steel(!) 57 mm case in such a way that it has a neck starting at 42.5 mm --where wall thickness is considerable-- must have been a difficult undertaking. Doubtless it was done in multiple steps, but I am not surprised that the case buckled under the large forces necessary.”

Finally I contributed:

Great information!

Good questions. This distortion only appears on one side of the cartridge and I intentionally took the scan to show the distortion. I thought it was from case resizing. The neck below the bullet has a slight depression of less than 0.1mm on average when compared to the case mouth, both the case mouth and the neck below the bullet have more variation than this when measured at different points around the circumference.

The round looks like it has been through a fire or otherwise blackened.

The individual who gave me this item was commissioned in the Ordnance Corp before WWII. He went to England well before D-Day commanding the US Foreign Weapon Evaluation Unit as both a Major and Lt Col. I suspect he and Jarrett would have been well acquainted with each other. He and his guys assembled the first Stg44 the allies got their hands on, from captured parts of destroyed guns, and he fired the weapon and wrote the first allied report on the weapon. He had a copy on his bookshelf and, as I remember, it was dated shortly after D-Day. He was very proud of this. He considered it a good weapon when fired semi-automatic but was pretty dismissive of its effectiveness fired fully automatic sweeping an area.

It sounds like this is likely the 7.9x42.5mm or something in the family! Guess I will put it in my cabinet with my other neat non-9mms.

Any other information appreciated. Dutch probably has something insightful to contribute!


That is the relevant material to date.

I have found the following images of the Heinemann rifle from the late 1920s.

The 276 Pedersen version mentioned by Fede:


I could find no information on the German riHeinemann rifles or the 7.9x42.5mm cartridge, or any related cartridge.

I would like to find out more about this cartridge and/or the gun that fired it. Even an image of Bill Woodins note would be appreciated.

Anything on this cartridge and associated weapon(s) would be apprediated.



Lew, here is a picture of the variant in 7.9x42.5. I’ll look for more information as soon as I can.




According to Dieter Handrich in his book “Sturmgewehr 44” (published in Germany 2008, p. 89) the weapon shown by Fede, serial number 07, is part of the NRA Firearms Museum collection.
According to Handrich, engineer [Karl] Heinemann of Rheinmetall developed this weapon for the 7.9x42.5 cartridge in 1927. It used the ordinary 10 g S bullet. The [missing] magazine was horizontally inserted from the left side.
The Handrich book first was published as an English language book by Collector Grade Publications and copies should exist in the U.S.

Edit: If the NRA agrees to make a chamber casting, we could get good information about the authentic case dimensions.

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Just as the example from Lew, the Cassel (Kassel) case was blackened
This was not normal. I would say it happened later.
This means also by the development they used cases to make the 7,9 x 42,5 with different head stamps.


There is also a round in the Woodin Lab. As far I remember, that round was found after WW2 in the company, Krieghof in Suhl.


Is it possible to make one from two?

I decided to start a new thread because the old one was just a simple question and the thread went in other directions. Sorry if I confused you.

I can cut and paste some of the other thread here if it would help.

Thanks for the great information. I assume the Cassel round above is from your collection. Great item! Mine might look a bit like that if it was carefully cleaned up! Could you share a bit about the origin of this round later this week when we see each other, or in a PM or both?

Do you have any information or images on he round in Bill Ws collection?

How many of these are known in collections?

Look forward to seeing you. If you answer all my questions, perhaps I will even buy you a “Dutch” beer…


Lew, in the meantime I received a copy from an article in the German magazine. (396-19)
It was written by P. Regenstreif were he described this cartridge he was studying in the Woodin Lab.
The head stamp of this round is; C / 6 / SE / 18 /
He also write in this article that Heinemann was working these day’s at Rheinmetall-Borsig in Sömmerda, later by Mauser in Obrndorf.

I can show you this article if we meet at the international show in the Netherlands.


P.S. only one beer. :-)

Unfortunately I am not so familiar with rifles.
A friend told me that the Heinemann rifle is the one in the middle.


Dutch - unless one of those is some totally different version of a semi-auto rifle by Heinemann, none of them are the rifle in question. The picture Fede posted is the shorter version of the Heinemann development.

John M.

Willem, that is not a Heinemann but a very rare Siemens prototype in 7.9x57. Top is a Scotti Mod. X and bottom a Mauser G-35.



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Sorry, guys,
I am not so familiar with Rifles. :-(

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If you judge Siemens’ quality by their coffee makers, I would’nt want that rifle even if it was thrown after me!!


Is the source of the image known ?


a very fitting description of Siemens of today.

the photos shows a display at the Wehrtechnische Studiensammlung, Koblenz (top floor). I am not sure if this combination of rifles is still shown.

Thanks Peelen,I had thought it was at Koblenz !!! ,some really unique pistols still there ?!