20 X 102 pressure test

[Slick]

Ran across this while looking for something else. There's an assorted box of them, so it's not like I inspected every one, but this one stood out. My educated guess is this was used in testing. A slight bulge with a perforated "half moon" impression midway on the case. No headstamp or other markings. I'm slightly familiar with this sort of testing but not so much as I know anything. Maybe someone has info on the test equipment they can share.

 

[kahu1]

Don't know if that is a sign of pressure testing, most fired Oerlikon(20 x 110RB) cases have a similar 'half moon' impression, i always thought it must be something to do with the ejection mechanism of that particular cannon.

 

[kahu1]

Pics of Oerlikon 20x110RB with similar markings on case.

Note the middle case appears to have a more raised marking ,might be due to having been polished.

cheers
Bob