US Experimental manufacture of 23 x 133 HS 827 ammunition


At SLICS I got an experimental US made case in 23 x 133 Calibre. The fininsh is a very light matt green plating. The markings are (printed on side of case in black ink):

23 MM

Apparently these are very rare to find as loaded rounds, but the unfired cases are fairly common. Can anyone tell me any more about what this case was intended to be used for? Was it an aircraft gun, anti aircraft, helicopter, AFV etc?

Thanks in advance for any info.


Are you sure the dimensions are the same as the HS 406 case? Considering that this was a 1930s French prototype which never got into service, it would seem rather odd for the Americans to be copying it in 1969.


I have the same ink printed case: 23x133 AMRON
No information.


Sorry, I meant 23 x 133. I have edited my post to remove the error.


Falcon, this might be the right one…


This cartridge is referenced 23x133 US XPL Amron in my software “ECRA Caliber Data Viewer”.
It is not the same that the 23x132 HS 827C.



There was a french lacquered steel case on the SLICS table I got my Amron case from that was identical when compared side by side. What is the difference between these two calibres?

On the internet I found out that Amron are still around today, and located in Antigo, WI. Would this case have been made there in 1969?


I also bought one of these cases at SLICS and it piqued my curiosity. If nobody beats me to it, I will see if I can do some research on it at the Woodin Lab and write an article for the Journal.