7.7x58mm Jap SR Tracer


#1

I could really do with some help to identify these two Japanese 7.7mm semi-rimmed tracers!
The round with the green primer (right) is, I’m almost certain, a Type 92 Tracer.
I bought the other round (left) which had been labelled as a ‘Type 89 Tracer’ thinking I had filled a gap in my collection. As far as I am aware Types 92 and 89 are dimensionally identical variations of the same case-type.
Whilst checking my new cartridge with Ken Elks ‘Japanese Ammunition 1880-1945’ he clearly states that the Type 89 series was produced in four loadings only - ball, armour piercing, and two variations of incendiary. It appears that there never was a Type 89 Tracer.
Both these cartridges are of the same case type, i.e. semi-rimmed, and both are tracer as indicated by the green casemouth seal. However, there is a very noticeable difference in bullet ogive, the bullet with the green primer having a rounder profile and being 0.8mm shorter than the other round.
What is the round on the left?



#2

Hi Jim
According to my husband the rim on the type 89 should measure 12.72mm and the type 92 should be 12.62mm. This is apparently the only difference.
Carolyn


#3

Hi Jim,

I assume you have correctly identified both of these cartridges as the SR type 7.7.

My guess is these are both Type 92 tracers.

Ken Elks states in his book, the Type 89 ball was made from gilding metal, the AP was made of brass, and the incendiary Type 92 was made of cupronickel. Neither bullet above is the Type 89 explosive Ma 101.

Both cartridges #1 and #2 are cupronickel bullets, which would mean if it were a Type 89, both would have a magenta case mouth seal. Both cartridges have a green case mouth seal. Therefore, green case mouth seal and green primer are not associated with the Type 89 in any way.

Elks also states the Type 92 used the same case as the Type 89. Therefore, dimensionally there should be no significant differences between the two.

The Type 92 semi-rimmed was developed in 1932 and the Type 99 rimless was developed in 1937. Type 99 ammunition could be fired in Type 92 weapons without malfunction, but the reverse wasn’t true.

Elks noted that cartridges from opened packages of Type 92 from 1938 onward all had green or blue-green primers lacquered primers. The green lacquered primer was used to tell the difference between Type 92 and Type 99 ammunition and occurs on several varieties of Type 92 loadings including ball, AP, etc.

My interpretation is cartridge #1 is a pre-1938 Type 92 tracer. It has a clear lacquer primer which would be appropriate for the 1932 to 1938 era before the advent of the Type 99. The bullet is cupronickel which is correct for Type 92 tracer, and the green case mouth seal wasn’t used for Type 89 ammunition, but was used for the Type 92, Type 97, and Type 99.

Cartridge #2 is a post-1938 Type 92 as it has the green lacquered primer to distinguish it from the rimless Type 99. It has a cupronickel bullet and a green case mouth seal, which would indicate a tracer.

Have said all of the above, the Japanese did create an odd and confusing system for ammunition identification. After examining several pieces of Japanese small arms ammunition, I sometimes wonder if they could even follow their own system.

I hope the above information is correct and helps answer your question.

Heavyiron


#4

Good, informative post Heavy.

You made a good point about wondering of the Japanese were even able to follow their own confusing marking system. The only job in the Japanese army worse than being a latrine attendant had to have been being a supply officer…

AKMS


#5

Wow, seriously confusing stuff! Heavyiron, thank you for such a clearly laid out response. I actually have Ken Elk’s book in front of me and I still can’t figure it all out…


#6

Heavyiron, I just put a magnet to these two bullets - the round on the right with the green primer is magnetic; the other is not!
Elk’s book doesn’t make it clear whether the Type 92 Tracer bullet is or isn’t magnetic however this certainly suggests my two bullets are not the same. The difference in their profile is also, I think, of relevance.


#7

Jim: From the magnet can you tell if it’s the jacket that’s magnetic or the core? I don’t think the bullet is a Japanese army type, but knowing whether the core or the jacket is magnetic would help tell what the bullet might be. JG


#8

I don’t often use a magnet so I’m not really confident what I’m checking for but the magnet seems to be evenly attracted for the length of the bullet. Does this suggest that it’s the jacket which is magnetic?


#9

Jim–Apply the magnet (preferably a weak one) to the very tip of the bullet. If it is a Steel Jacket only, the magnet will be attracted the same as to the side. But, if it is steel cored, it usually will be attracted less at the tip and considerably more on the side.


#10

Thanks Ron, using a weaker magnet makes it a lot easier to measure the attraction. The attraction seems to be pretty consistent along the entire exposed part of the bullet and right to the tip.
For the record, the round is still live and the green casemouth seal appears intact.


#11

Curiosity and impatience have got the better of me and I have dismantled the cartridge shown on the right with the green primer.
J.G. was quite correct - this is not a Japanese Army tracer round. The bullet is a lead-cored ball bullet and in shape appears to be a Type 89. Why it’s been marked as a Type 92 Tracer I have no idea.
Ken Elks suggests that 7.7mm Semi-rimmed ammunition was captured and remarked by the Chinese post WW2. I have got one of the remarked Armour Piercing cartridges that he describes.
My guess is that this is a ball round captured and remarked by the Chinese.