Long life to all the Feds! But I don't totally agree with you when you say that your Fed is a transitional model. If I try to summarize: -The Fed NKVD 1b are engraved "YCCP" with serial numbers from c. 6000 to c. 55000 and round covers. -The 1c show the same engravings but with cornered covers. Probably to put the mechanism of the 1B, as you said. Serial numbers: c. 55000 to c. 92-95000. -As for the 1d: CCCP engravings, serial numbers till c. 176000 and two other changes compared to the 1c: 1- the central screw half hidden behind the lens rim is now completely visible, 2- the three screws under the rewind knob are no more visible.
There are transitional models between # 92000 and 95000: Fed gradually introduced the two above changes. And it seems that the second change was introduced the first and the new CCCP engraving was the last. To be more complete, there was between c. # 80-82000 an other modification: the base plate pin was enlarged to 5mm (from 3mm).
All that seems perhaps quite complex, but it's nothing compared to the multiple evolutions of the 1b!
Amitiés. Jacques. PS: so I think that your camera is a plain 1d.
I've finally been able to sit down and examine the camera once more. You seem to be absolutely correct, the only reason I've called it a transitional model is because my serial # falls outside the range of Jean Loup's classification of 1d... He says 1d serial range is 125,000 to 174,000/180,000.. mine is 115347 which is 10,000 BEFORE 1d according to him and well into 1c range.. so thus the confusion.. so is he wrong in this instance? Seems like 1d was introduced earlier?