Swiss 7.65mm Amsler ID

I have found these images in the web which were labeled “Swiss 7.65mm Amsler”. No other info was given.
Obviously experimental stuff.

As per the design of that irregular shaped case it appears like something along the Dardick-Tround system with open and rotating chambers.
The cylindrical one seems to have an adaptor inside the case neck and is basing on a draw stage of a 7.5x55 case…

Anybody to tell more about these?
Is the case length known?
Do better images, diagrams or reports exist?






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No Swiss members responded, so I will give it a try. Amsler is the name of the designer at SIG who was largely responsible for the Swiss assault rifle Stgw 57. Its prototype was designated AM 55 after him.
I recommend contacting which may have more information. In particular, Eduard Brodbeck, a leading SIG designer involved in creating the later gas-operated line of assault rifles in the seventies, might know some details.
On the other hand, Amsler is not a rare name in Switzerland and it could be a different person.

Jochem, thanks a lot!
I thought these odd looking cartridges should be well known amongst those who care.
As Switzerland is not my area I will leave it to others to contact SIG or other entities.

Hi Alex, these are experimental cartridges for the “Trommel-Schüsswaffe” designed by Rudolf Amsler (1900-1979) in the early 70’s. Like Dardick, he developed an open chamber design having a drum with capacity for multiple cartridges. Amsler was the chief designer of K+W at Thun and director of SIG since 1945.

548580.pdf (361.7 KB)

548584.pdf (208.3 KB)



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Fede, thanks a lot! This is most interesting as I was not aware of this development line.
Also I missed to search for patents.

What is the case length of these cartridges?

Are images availabe of the gun?