Alex, here is a new compilation of the timeline for cartridges headstamped JR, M, Z, P14A, dou., and PS. I’m not ignoring what has been published before but there are some discrepancies that I’m not able to verify and sometimes the only option I have is to choose what seems to be the most trustable information (the information given for the period between 1928 and 1925 is the most conflictive). Cartridges made by Zbrojovka Brno a. s., závod III, Vsetín (today’s ZVI, Inc.) and post-1995 PS are not included.
I’m sure that there must be lots of mistakes and omissions but let’s hope these can be corrected.
G. Roth, Pressburg
Bratislavská J. Roth a. s., Bratislava (Czech designation)
Bratislavaer G. Roth A.-G., Bratislava (German designation)
Bratislavai Roth Gy. R.-T. (Hungarian language designation)
January 1, 1918
Pressburger J. Roth A-G.
Also listed as “Preßburger G. Roth AG, Munitions-, Metallwaren-und Maschinenfabrik, Grau- und Metallgießerei”.
October 28, 1918
Sometime after this date, in which the first “Československá republika” was proclaimed, the company name was registered as “Bratislavská J. Roth a. s.”. The name of “Bratislava” was officially adopted on March 27, 1919, meaning that it could have happened after this date.
The first known dated “JR” headstamp is 19 / JR / 23 / IV / (8x50R).
July 29, 1925,
First use of trademark “Z inside rifled barrel bore” registered by Československá Zbrojovka a. s., Brno.
March 15, 1928
Sometime after this date Zbrojovka Brno bought most of the shares and changed the Roth company designation to “Československé municní a kovodelné závody a. s., Bratislava”. They also decided to establish a second new factory at Považská Bystrica.
The last known dated “JR” headstamp is 19 / JR / 28 / XI / (7,9x57).
The first known dated “M” headstamp is 19 / M / 29 / V / (7,9x57).
June 24, 1929
Excavations are made for the foundations of the new factories.
July 7, 1929
Construction of both factories starts at Považská Bystrica (ex-Bratislava and new one). Ceremony of foundation stone is made.
October 25, 1929
G. Roth A.-G. of Vienna decided to dissolve the company, including the one at Bratislava.
January 10, 1930
G. Roth A.-G. of Vienna in liquidation.
All shares of “Československé municní a kovodelné závody a. s., Bratislava” now belongs to Zbrojovka Brno a. s.
June 30, 1934
The Bratislava production was moved to Považská Bystrica and its designation is changed to “Československé muničné a kovodelné závody, a.s., Považská Bystrica (bývalá Patrónka Bratislava)”. The second newly constructed factory is designated “Československé muničné a kovodelné závody, a.s., závod II, Považská Bystrica”.
The first known dated “Z” headstamp is 19 Z 34 7.65S (7.65x54).
January 1, 1935
Both factories fusioned under the name of “Zbrojovka Brno, a. s., závod II, Považská Bystrica”.
June 19, 1935
Trademark “Z inside rifled barrel bore” registered by “Zbrojovka Brno, a. s.”.
The last known dated “M” headstamp is 19 / M / 35 / XII / (7,9x57).
German designation for the Považská Bystrica ammunition factory listed as “Waffenwerke Brünn A.G., Werk Povazska Bystrica”.
August 5, 1940
Shares of Zbrojovka Brno a. s. are bought by Reichswerke A.-G. für Erzbergbau und Eisenhütten “Hermann Göring”, Berlin.
The first and last “P14A” headstamps reported are P14A * 5 40 to P14A * 55 40 (9x19) and P 14A XIg1 1 40 to P 14A IXg1 19 40 (7,92x57).
The first known “dou.” headstamps are dou. IXg1 1 41 (7,9x57) and dou. 41 2 * (9x19).
Zbrojovka Brno a. s. is incorporated to Waffen-Union Škoda-Brünn G.m.b.H., Berlin.
The first known steel cased dated “Z” headstamp is Z St 1 42 (7.9x57 and 9x19).
The last known steel cased dated “Z” headstamp is Z St 7 43 (7.9x57).
The last known brass cased dated “Z” headstamp is 19 / Z / 44 / III / (7,9x57).
The last known “dou.” headstamps are dou. -St+ 7 45 (9x19), dou.-St 9 45 (7,9x33) and dou.-St+ 14 45 (7,9x57).
July 23, 1945
Trademark “Z inside rifled barrel bore” registered by “Zbrojovka Brno, a. s.”. Use in ammunition is mentioned.
October 27, 1945
Zbrojovka Brno, a. s. is nationalized and became “Zbrojovka Brno, národní podnik”.
March 7, 1946 (with retroactive effect from January 1st)
The ammunition plant at Považská Bystrica became independent from Brno and renamed “Považské Strojárne, národný podnik, Považská Bystrica”.
The first known dated “PS” headstamp is 19 PS 46 IX (7.9x57). There is an illustration of 19 PS 46 II but I’m not sure if it does exist.
April 19, 1947
Trademark “Z inside rifled barrel bore” registered by “Zbrojovka Brno, národní podnik”. Use in ammunition is mentioned.
April 20, 1950
The “KOVO” trademark is noted as first used. This was the company offering products by “PS”. Full designation was: KOVO, akciová společnost pro obchod s kovodělnými a strojírenskými výrobky a surovinami, Václavské náměstí 56, Praha 2 (KOVO Limited, metal and engineering products and raw materials trading company, Wenceslas Square 56, Prague 2).
There is catalog that shows year 1949 on the cover but this is a reproduction and this date would be wrong as the company name didn’t yet existed.
The last known dated “PS” headstamp is PS / * / 7,65 / 52 / (7.65 mm Br.).
September 8, 1952
KOVO’s name changes to “KOVO akciová společnost pro dovoz a vývoz výrobků přesného strojírenství, Tř. Dukelských hrdinů 47, Praha 7” (KOVO Limited, import and export of precision engineering trading company, Tr. Dukelskych hrdinů 47, Prague 7).
The Company name is noted in boxes illustrations as “Považské Strojárne, národný podnik” and “Považská Bystrica” is not shown anymore (Suplement to the Catalogue of Pistol, Revolver and Rifle Ammunition available in 1952-53).
Edit: Z St 1 42 headstamp in 9x19 added.