I am curious if anyone knows of an English language source with information on the 7,62X122R round, and some of the other similar experimentals.
You certainly mean the 7.62x93 and the 7.62x125SR.
If my memory serves me right nothing else is known but what the Russians have published about and what was translated into English then by various people.
As per Russian sources there is very little known about and they are not AT rifle cartridges as way too often interpreted in the west but they were meant for aircraft guns.
in p regenstreif book “russian small arm amunition” there are a 7.62x122R mentionned
look like a lengtened “8x57 R -.360” with very small shoulder
do you had a drawing of the 7.62x125 SR
We are talking about the same cartridge here which is a “SR” (small groove above the more standard looking rim), it is just hard to see on the images which had been around in the past.
If I am not mistaken the case is 125mm as the published 122mm are originating from measuring the photo and the 125mm were provided by somebody who actually handled the cartridge.
in my book my picture is well clear to see a rimmed case and not a sr case
no even small groove visible
I looked up some other pubs, it seems there is a rimmed only version too.
As mentioned the 122R. Properly rimmed round, not a semi-rimmed. I was hoping something easy to read was out there on this round, and the 125.
there the title of the book
“munitions militaires russes” (russian military ammo)