Unknown 20 mm tool cartridge 20x135 / 20x139

There are some questions on the tool cartridge shown on the pics.

It’s said, that it’s a - maybe unknown - german trial-caliber 20x135, but the known ones have other cartridge case-proportions. The dimensions are really near the post-war 20x139.
It’s said, that the cartridge case is made of brass.
In my opinion, the headstamp could be a fake: P , Ex , [eagle]WaA 75, 34

Did someone got a similar cartridge and knows the right caliber and the origin?
All answers and - hopefully - declaring pics are very wellcome.

Thanks for support.


Is this cartridge different from the 20 x 135mm (Polte) for the Mauser MG213C that is listed and shown on Tony Williams’ web site? The profile looks to be about the same but the only dimensions I see are a rim dia. of 32mm.

I have no other references to this round besides Mr. Williams.


Hi DaveE.

Dimensions and geometry of this tool cartridge are different from the 20x135 of the MG213C.

Rim-diameter here is said 28 mm, extractor groove diameter 24 mm, case diameter where shoulder beginns 26,5 mm, neck length 12,7 mm. Case length should be 135 mm, but measures at the pics give some 138-139 mm.

AND: The developement of the MG213C starts middle 1942, the headstamp here shows “34” …

If it’s really an unknown and not adopted trial-caliber, why does it have an acceptance stamp like adopted ammo? I think this is a contradiction in terms.

The cartridge is for sale. First the seller told, that it is a 20x138B for the 2 cm Flak 38. After I corrected this, he told a story, that he get it from an officer who was detached to an army trial station (Heeres-Versuchsanstalt) … a little bit unprobable, or not?

Did you buy the cartridge? If it was cheap I would have “bitten the bullet” so to speak, and bought it.

No, I don’t. If I had, I could post better pics.

AND I’m not collecting fakes - if it is one ;-)

Right this is the problem I want to solve.

How much was he selling it for? I’d be willing to spend up to

I found this picture in my archive. It looks similar, but says 1936 as the date of the experiment.

I have one question about this: Did trial ammunitions got acceptance mark? They were made only for a firm, not for the military.


This article on my website may be of interest, although I don’t know if it answers your question: quarry.nildram.co.uk/fakes_and_replicas.htm

This is the photo from it: