Military Guns and Ammunition

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This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

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Swiss twin 34mm AA gun (post-WW2)   Army Guns 20+mm

Started 1/3/19 by Petrus_Optim; 620 views.

From: autogun


Thanks for posting, not seen those pics before. A paragraph from my next book (with thanks to Bob Gerber):

34 mm HSS 834 and 40 mm HSS 840: 34 x 239 and 40 x 239B ammunition.

In the early 1950s the Kriegstechnische Abteilung or KTA (Weapons Technology Section of the Swiss Defence Ministry) requested Hispano-Suiza to develop a new heavy automatic AA gun intended to replace the 34 mm Flab K 38. The resulting gun was was designed in two calibres: the HSS 834 which used an updated loading of the existing 34 mm ammunition; and the HSS 840 which used a 40 mm version of the case, with a belt added to ensure accurate headspacing. Ammunition feeding was via a linked belt or five-round clips and the cyclic rate was an impressive 450-500 rpm.

The project was shelved in the mid-1950s. Oerlikon eventually replaced the Flab K 38 with their KD series guns (see below).

In reply toRe: msg 2

From: Petrus_Optim


At there is some info on a 40x270 cartridge by Hispano-Suiza. Original Czech description may be translated as follows:

"An experimental cartridge built in Switzerland in the late 1940s, probably for an anti-aicraft cannon. During trials it developed a muzzle velocity around 1200 mps. Further information on that project remain unknown".

It's interesting that the Czech website is the only place over the Internet that contains any remark on the 40x270.

Which gun was this cartridge intended for? Was it a derivative of the HS-840 (for 40x239B) or quite a different design? Obviously its ballistic performace is interesting too.

Any thougths?