Japanese 20x71RR Bunter error?

My Japanese Navy 20x71RR Type 1 Oerlikon fired case has an odd date at 9 o’clock.
It is clearly stamped 60. Usually you see 01 or 02 in this position.
This cannot be 2606 (1946) 06 or 09 reversed. Is it for 2600 (1940)? or a bunter error by someone not familiar with western numerals?
Has this headstamp been noted before? All comments are welcome.20x71%20H%3AS


Most interesting headstamp. Looks much like made by Oerlikon.

It seems to be made by Dainippon Arms Co, Japan.
Mk 1 case from December but in what year?

Not really my field, I was going by the appearance of the font and design.

Maybe somebody has an Oerlikon 20x72RR headstamp on hand?

Some thoughts that raise more questions.

Could 60 be 1960?

The US transferred naval vessels to Japan’s Maritime Self Defence Force in the mid-1950’s. If these vessels included 20mm Oerlikons, would they have used 20x71RR?

Was the ni kanji headstamp still in use in 1960, either by Dainippon Arms Co., or by another company?

US ships usually had 20x110RR Oerlikon guns.

The 20x72RR Type 99 was an aircraft gun.
So far I have not seen any such guns in use after 1945. Maybe some countries used Japanese aircraft after 1945 using up stocks of old Japanese ammunition but I doubt any new was made.

Ron, I can’t think of anything that could relate to “60” with this cartridge. The closest thing that comes to mind is if as you say using the Koki system of dating the year 2600 (1940) would be a very likely manufacture date for that cartridge but still would constitute a bunter error.

I will just add to my response that I am looking for Belt links for this cartridge as used in the Japanese Type 4 gun if anyone can help.


I am looking for Belt links for this cartridge as used in the Japanese Type 4 gun

If you find any, please post a photo!

Were the links the same for the 20x72RB as for the 20x101RB?

I thank everyone for their thoughts on my headstamp. I even contacted Ken Elks and he had not seen this before and suggested I use this forum .My analysis from answers seems to be a bunter error for 2600 (1940) . Please prove me wrong.Cheers.
I know nothing about the links question.

First of all, apologies to Ron, I did not intend to ‘highjack’ his thread regarding the Links.

Tony, Good question as to the commonality for the links between the Type1 and Type2 cartridges. A display at SLICS featured some Type 1 in Links. I had already intended to contact the owner (a specialist large calibre Link collector) to see if some close up pics of those Links was possible. Others may also have the answer to your question. Watch this space…