I found this cartridge at a Washington Arms Collectors show a couple of years ago. I
initially thought it was the result of idle hands and imagination. I was wrong. After a
little digging in my library, I found a nice article by Ian V. Hogg (Encyclopedia of
Firearms, 1987, page 82).This article shed a little light on the true heritage of the
cartridge. The case seemed to be a 20mm Oerlikon cartridge case cut down. I was close. It
turns out that the 20mm Oerlikon cartridge was based on the 19mm Becker Cannon cartridge.
Check the rebated rim and rounded web of the case base. The key for me was the
It has an August 1916 date. The 20mm Oerlikon cartridge was not introduced until about
1930 so it couldnt be a cut down 20mm Oerlikon case.
The following is a little information drawn from Ian V. Hoggs
The 19mm Becker Cannon cartridge was developed in 1916 by two German
brothers by the name of Conders. The Conders brothers were employed by the Stahlwerke
Becker of Reinickendorf, Germany. The cannon was an automatic weapon of blowback design
and used a differential locking system. The 19mm Becker Cannon cartridge used a high
explosive projectile with a contact detonator. The cannon had a 15 round vertical feed
magazine and could be fired either in single shot mode or in a fully automatic 300 rounds
per minute mode.
It was reported that the Germans used the 19mm Becker Cannon as an
anti-aircraft gun with some used on Gotha bombers. It is believed that there was less than
400 cannons manufactured.
After the end of the First World War the Stahlwerke Becker company was
not allowed to manufacture any firearms. To remain in business, they sold their patent
rights to a Swiss company, Maschinenbau AG of Seebach. Maschinenbau AG made some
modifications to the basic design of the cannon and marketed it as the Semag-Becker Cannon
for use as an infantry support weapon. This marketing was not successful and the company
went into receivership in 1924. The patents, weapons, staff and machinery were acquired by
the Oerlikon Machine Tool Company of Switzerland. The cartridge was redesigned to a use a
20mm diameter projectile and the case was significantly lengthened. This redesigned case
became the famous 20mm Oerlikon cartridge.
The case is brass with a Berdan primer 0.430 inches in diameter. The
projectile is hollow and turned from steel with a bronze driving band and a lead alloy
nose with a spring loaded contact fuse or detonator. This can be seen in the image detail
of the nose piece. Why was there a hole crosswise completely through the nose? I am
assuming it was for an insert to safe the cartridge during handling. Note the
pin extending into the hole. The cap is spring loaded and when pressed, the pin extends
through the crosswise hole and into the body of the head detonating the projectile. Can
anyone add to this?