- Unfortunately I am unable to post my own pictures on this excellent forum using my slow “WebTV” but “sksvlad” will do it for me. — I have a fired brass 20X138B belted shell case Long-Solothurn manufactured in 1941 in Finland. Clockwise from 9 o’clock position, the imprssed headstamp markings are: “E4”, a circle with 2 crossed arrows, “20/40”, “T” and “41”. I’m sure “41” is the two digit date for the year of shell case manufacture  and the letter “T” shows the maker “Tikkakoski Arsenal”. Anyone who knows the meaning of the other headstamp markings??? — NOTE: A] The 20X138B round was also used by the German “FlaK 30-38” light AA guns and perhaps other models. B] I assume my 20X138B brass shell case made in Finland was fired by the “20mm Lahti Mod.39 anti-tank rifle” also manufactured in Finland. C] Note on the 20X138B shell case head [at 1 & 7 o’clock positions] the heavy markings left during the extraction and ejection process. Thanks in advance for any help, Liviu 12/31/06
Here is Liviu’s photo. La Multi Ani to everyone!!!
- Thank you “sksvlad”, I’m very glad you can help me posting my pictures. Note in my photo from above that a “O” or “0” mark overlaps the number “2” of the “20/40” headstamp mark. Liviu 12/31/06
Presumably Liviu is still looking for answers on this.
- Yes, I’m still looking for some answers. The same photo and questions can be seen on page 51 of the IAA Journal #455 [May/June '07]. Liviu 07/05/07
I’m sorry, I can’t help with the headstamps.
As a matter of interest, the guns which used the 20x138B “Long Solothurn” start with the Solothurn S5-100 series, which was the ancestor of the Rheinmetall-Borsig FlaK 30/38, the KwK-30/38 (used in light tanks and armoured cars) and the MG C/30L (designed for aircraft, but mainly used as an AA gun). The round was also used in the Solothurn S18-1000/1100 anti-tank rifles.
Outside the Rheinmetall/Solothurn family, the 20x138B was used in two Italian guns - the Breda M35 and Scotti - as well as the Lahti L39 anti-tank rifle and L40 AA gun. It was also used in Polish guns (the 20mm wz. 38 HMG family of ground and aircraft guns), but these saw little use.
Just a remark, the Polish 20x140B is not interchangeable with the 20x138B Rheinmetall. These cartridges looke very similar but have different case measurements.
Not to forget Russian pre war (for the M30 AA gun bought from Rheinmetall) US war and Norwegian, Czech and Yugoslav post war manufacture.
I have a round with a similar, but not exact headstamp. I’m sorry I can’t help with what the characters/numbers represent. 20mm is about 12mm larger than the cartridges I collect.