7.7mm Japanese Semi-Rimmed box Markings

Can anyone tell me what the markings mean. On the 30rd strip there were 3 rds with the green coloured primer. All the bullets look the same though. I assume those 3 are Tracer ?

My mistake this is 7.7mm Semi Rimmed NOT Rimless

Could a MOD change the topic title please.

Mr. Armourer

I don’t know the answer but would like to piggy-back on your question.

The cartridges in my clip all have a red seal around the bullet cannelure. What does that mean? I also have some with the green primer seal (not in the clip).

Those Jap cartridges are a real mystery to me. Maybe someone can answer your question and explain all the other colors while they are at it.



As far as I know on Japanese manufactured 7.7mm Rimless ammunition, a pinkish red/reddish pink casemouth seal denotes Ball on Type 97 Tank Machine, Type 99 Light Machine Gun and Type 99 Rifle ammunition.

But be aware that I think that on other Japanese ammunition a pinkish red/reddish pink casemouth seal may mean Incendairy (phosphorus) so mind them fingers if you’re unsure !!!

I only recognize a few of the characters on the label (for example, reading downward in the right column it says “92 heavy machine gun”, meaning these should be the 7.7x58SR rounds for the Type 92 “woodpecker” MG (though it could also use the rimless rounds used in the Type 99 box-fed MG, as long as they were loaded in strips). The markings can be a real bird’s nest to work through, since some of my books say that the Army and Navy used different colours for some of the identical loads. Generally, it’s agreed that pink = ball, green = tracer, black = AP, red = incendiary, and purple = explosive (but other books say red/pink = ball, green = tracer, black = AP, magenta (purplish-red; how could they possibly make this MORE likely to screw up?) = incendiary, and none of them explain the very light (almost white) neck seal on the explosive rounds that I’ve seen).

SDC thanks for that.

I’m just adding some more info and answering my own question re Green primers.

Type 92 Heavy Machine Gun 7.7mm Semi Rim: Ball, AP and Blank can have Green or clear lacquered primers.

And while we’re at it, tracer bullets for army small arms ammunition should ordinarily have cupronickel jackets. Naval ammo, mostly 7.9m/m and 7.7m/m rimmed, and its coding is an entirely different complicated story. JG

The green primer [seal] should indicate boat tail ball loading.


I can add a little more detail to the earlier translations.
The left hand column of four characters denote the ammunition type of which the lower two indicate “live” cartridges. The upper two should be bullet type, my strip has ball rounds and my top two characters indicate “normal”, so combining all four = normal live rounds. Your upper two characters are different so presumably some other live loading.

The bottom line has a character for “Showa era” followed by 15, 10. This means 1940, October.


Thanks all for the information.

I thought I’d pull the rds to see what I’ve got. These rounds have in the past been inerted so it’s possible that the bullets are from elsewhere.

Neither bullet has a core ???

The left hand bullet dia is 7.90mm and the hole for the core is 3.57mm, the bullet is stained/blackened all over.

The right hand bullet dia is 7.83mm and the hole for the core is 4.29mm the stain/blackening is patchy.

All the 30 rds on the feed strip are stained/blackened, some rds have a pinkish casemouth seal.

All the rds weigh the same give or take a little so I don’t think any bullet has a core to it .
Any thoughts Gentlmen…

I don’t think the primer colour is of any relevance in this calibre and Conjay’s shows examples of all the below loads having both clear & green primers. The different loads are identified by their casemouth seal;
Ball - pink
Tracer - blue/green
Armour piercing - purple/black
Incendiary - magenta
Explosive - purple

The cases that have traces of a pink mouth seal were originally loaded with the gm jacketed boattail bullet of 7.9m/m (.311 in.) diameter standard for the type 92 7.7m/m HMG; the rest are unknown. The coreless bullets were apparently recycled from .30-06 and .303. JG

Ken Elks in the latest edition of his “Japanese Ammunition 1880-1945. Part 1” says that green primers were introduced between 1938 and 1941 on Ball, AP and Tracer Type 92 ammunition, and was present on all subsequent production.

He thinks the colour was simply to differentiate it from 7.7 rimless Type 99 and so prevent its use in machine guns chambered for the Type 99. He says the green primer was absent from 7.7SR incendiary and explosive cartridges because these were exclusively for aircraft use where the possibility of confusion would not arise.

Not very long ago, one of our Forumists said that he was getting tired of re-cataloging a certain cartridge (I can’t remember which one it was). I’m getting that way with my very small collection of Jap cartridges. I’ve worn out several erasers and have used an entire ink cartridge trying to get them right. Anybody want to trade me something for them? :( :(





Armourer, I just found a list of translations in “Japanese Second World War Combat Weapons”, saying that the first two characters in the left row above “live cartridges” translate to “Ha Ko”, or “Pierce Armour”, so it appears that this box originally held AP rounds. Hope this helps.

SDC, thanks.