7.7 Japanese


#1

Can someone tell me what the rim dia. is suppose to be on the type 89 and 92 semi rimmed 7.7 cartridges
Carolyn


#2

Have measured half a dozen at random just now. 2 were 12.6mm, and 4 were 12.7mm


#3

Thank You
I assume the 2 are for the type 89 and the 4 are for the type 92


#4

Carolyn,

I measured what I call the rimless and semi-rimmed versions I have. The rimless come in at about .470" (11.94mm) and the semi-rimmed at about .498" (12.65mm). Those are average dimensions as they are not particularly round. I think the rimless I have is a Type 99 and the semi-rimmed is a Type 92. The Type 89 has the same rim as the Type 92. Don’t trust me on this as I am going by what I think I understand from all the help the folks here gave me on a thread I started a little while back. viewtopic.php?f=8&t=7536&start=0
Worth the read.

Dave


#5

According to Huon’s book on military rifle/MG cartridges, the measurements of Japanese 7.7mm are:

7.7x56R Type 89 for the IJN (otherwise known as the .303 British): rim diameter 13.44mm, base 11.65mm

7.7x58SR Type 92 for the IJA: rim 12.7mm, base 11.95mm

7.7x58 Type 99 for the IJA: rim 12.15mm, base 11.96mm

But actual measurements will vary to some extent (especially, I suspect, with wartime production).


#6

[quote=“CAROLYN”]Thank You
I assume the 2 are for the type 89 and the 4 are for the type 92[/quote]
Nope, all were from the same Type 92 feed strip.
My understanding is the Type 89 and Type 92 cases are the same.


#7

Sorry, you are right: I omitted one from my previous post.

The first loading of the 7.7x58SR was designated Type 89 and developed for aircraft guns. This was followed by the Type 92 which used the same cartridge case but different bullets; it was developed for a new land-service heavy machine gun.