20mm x 138B

Once they get over .50 caliber, I’m pretty much in the dark. I believe these are 20 x 138B cartridges. At the top is a pasteboard tube that holds one of the cartridges. Next down is a cartridge with a blue stained projectile with a white band, and headstamped 20/40 T 41 with an ‘x’ shaped symbol on a ‘O’. The next one has an orange-brown projectile marked 40/4 eagle over WaA732 with a white band, and is headstamped P six point star eagle over WaA700 36. The fired case is headstamped P315 IXa eagle over WaA648 39. What do the colors of the projectiles indicate that they are? Any other information would be appreciated. Rarity?

  • @ Guy H.: The 20X138B round right under the pasteboard tube is manufactured in Finland in 1941 [“41”] at Tikkakoski [“T”] arsenal. I don’t know the meaning of the other headstamp markings for this round. I have a similar fired 20X138B brass shell case [with no projectile] made in Finland and I asked questions about the headstamp markings [see on page 51, IAA Journal #455, May/Jue 2007] but nobody seems to have an answer. Liviu 01/27/08 P.S. That headstamp mark is actually a circle with 2 crossed arrows and there is also a stamp “E4”.

Finnish 20x138B:
20mm case model 1940, Tikkakoski, 1941, AP-T

Thanks Liviu and Hammer.


Congratulations on 90 years of Finnish Independance! :) :)

Tammisunnuntai (Did I use the correct word?? I do not know Finnish language.)


  • @ Hammer: Speaking about my 20X138B fired brass shell case made in Finlad in 1941, what is the meaning of the “E4” and the circle with 2 crossed arrows markings??? Liviu 01/28/08

“E4” is delivery lot and “circle with 2 crossed arrows” is acceptance marking.

  • @ Hammer: Very good, thank you! Liviu 01/28/08

Guy, the German brass cased round with the projectile was made at Polte Werk Magdeburg in 1936. “WaA700” is an acceptance mark. I am unsure of the meaning of the star. I believe the proj is an APT with white tracer (indicated by white band).

The fired case was made at [i]M

Thanks for the additional information. I have another example of the Polte brass case, this one fired, with the P six pointed syar and 20, plus an odd character that looks perhaps like a script ‘PW’ (Polte Werke??). This case is also brass.

  • @ Guy H.: Some German made 20X138B shell cases have an asterisk mark visible on the headstamp. I did not know the meaning of that sign and I asked the question, see page 35, IAA Journal #445 [Sep/Oct 2005]. The answer to my question was given by Mr. Jost-Burkhard Anderhub from Germany and it is printed on page 48, IAA Journal #447 [Jan/Feb 2006]. It has to do with the head thickness of some 20X138B shell cases. Liviu 01/29/08

The star on these is like the star of David, not an asterisk.

  • @ Guy H.: I don’t know for sure if both markings [asterisk & star of David] have the same meaning. I have 2 fired 37X263B brass shell cases of German manufacture, both dated 1938. At the same position on the case head, one 37X263B shell case has an asterisk and the other has the star of David. I assume both markings could have the same meaning but I cannot be 100% sure. Maybe somebody else can help … Liviu 01/29/08