Soyuz nerushimy, respublik svobodye, etc. I own both pre-war, wartime and post-war Soviet LTM RF's so I'll break this down for you.
Pre-war and wartime FED LTM lenses have a slightly different registration distance, different F-stops and everything. After WW2 they went to the Leica 28.8mm standard. This means that:
-Pre-war and wartime FED glass only registers properly on the cameras it was made for which are the NKVD FED (all types) issued to commissars and officers of the Soviet Secret Police
-Post-war Soviet LTM lenses are built to the 28.8mm standard
-Post war Soviet LTM lenses mount on Leica III-series cameras as well as Canons
-Post-war Soviet LTM Jupiter lenses are Carl Zeiss copies
-Post-war Soviet LTM lenses work and register properly on Leica/Canon RFs of the period
Now, regarding the old pre-war and wartime FED lenses
-They will mount on later Canon and Leica cameras
-They will not register properly but at infinity focus if you stop down to f/18 you'll get a usable image
-Once mounted, the red infinity line on the Soviet lenses will not line up with the top of the later 28.8mm LTM standard cameras, it's 1/4 turn to the right I believe
The sure-fire way to tell pre-war/wartime from post-war Soviet lenses is the F-stops. Pre-war and wartime goes f3.5, 6.3, 9, 12.5, 18
Postwar is f3.5, 5.6, 8, 11, 16>>3938965>>3938985
Jupiter lenses were all made post-war to 28.8mm standard so those are safe for the later Canons and Leica cameras.