Japanese 20 x 72RB case


#1

I have a japanese 20 x 70RB case with what look to be the following headstamp markings:

12 O’Clock: y

4 O’Clock: 1 - 11

8 O’Clock: 20

What is the meaning of these markings?

Thanks for any info.


#2

Imperial Japanese Navy Oerlikon Aircraft Gun (Short case).

Y is Japanese kana for “yo” (Yokohama Naval Arsenal)

20 is 20mm

1-II is Second Trimester, Year 2401 ( 1941).

Only the Japanese Navy headstamped their Ammo, mostly in the above 3x120 degree manner. (Kana Syllabary for Arsenal, Year-Trimester (During War) and Calibre in mm.). Some Naval ammo has a 4x90 stamps, and pre-War ammo has a Year-Quadrimester dating.

See Ken Elks “Japanese Ammunition” for better Details.

Regards,
Doc AV
A V Ballistics.


#3

The Japanese character resembling an inverted Y actually represents the sound “to” and indicates Toyokawa Naval Arsenal. Jack


#4

Thanks for the replies.


#5

Were these brass cases coated with any sort of lacquer? My case is coated in lacquer and it looks too evenly applied to have been done by a collector at a later date. If it is original I will leave it, but if not, I will remove it.


#6

Were these brass cases coated with any sort of lacquer? My case is coated in lacquer and it looks too evenly applied to have been done by a collector at a later date. If it is original I will leave it, but if not, I will remove it.


#7

Falcon, I do not beleive they were. I’ve seen quite a few different Japanese cartridge cases that have been lacquered. I’m under the impression that this was a common way to prevent the (war souvenir) brass from tarnishing. If I recall correctly, maybe in one of Fred Datig’s books, there is mention of lacquering cartridges to prevent tarnish. I think this was in fashion some years ago… It is not uncommon to see lacquered cartridges of all types at dealer tables at local gun and cartridge shows. In fact, there is a nice Japanese 25mm round at a local gun shop that has a lacquered brass case…

AKMS


#8

I also suspected that the lacquer was not original, so it will be removed.

Could anyone post some photos of original projectiles?

Also, what is the diameter of the projectile BELOW the driving band?

Thanks for any info.