P.S. there's a thread on here as to which FSUs can safely have the shutter speed changed before cocking and which cannot. However, there are two points to note. 1) it makes no sense on many models because the rotating dial can't show the set speed until cocked. 2) you have to be ham-fisted and force the winder actually to break the mechanism, although you can get them into a tangle, (mechanically speaking).
I've often wondered where and how this started; I looked in a FED 2's English instruction manual last night and there's no reference to it and yet it persists.
That reminds me that for the first model the instruction manuals were only available in Russian, probably because they were not exported until the late 1950's and/or early 60's when the FED-2 became available labelled in Cyrillic and Roman lettering with the earliest English FED instruction manual I have seen. So most people buying them online would have struggled to understand them.
Now looking at the FED-3 manual it mentions a restriction when setting the shutter speeds but that is to the effect that the speed's settings should be moved in the direction 30, B, 500, 250 to 2, 1 and back but never between 30 and 1.
There's something similar in the Zorki(-1) manual but the copy I have is in Russian. I think it says you should not move the setting between Z and 500 but go the long way round. (Edit) The manual says "В интервале межлу Z-500 диск поворачивать нельзя" and typing that in Cyrillic and using Google we get "In the interval between Z-500, the disc cannot be turned". Oddly enough they copied the Latin or Roman letter "Z" for this...
And in the Zorki-6's English manual it says "Never rotate the dial within the interval between "B" and "500", as in this instance the mechanism is likely to be damaged."
The Zorki 4's appear to be the first exported and I guess none before then had English manuals and so the same confusion may have arisen.
Looking quickly at the Leningrad, I suggest owners of them get a copy of Audrey Ostapenko's excellent English version of the instruction manual as it's a bit complicated...
Obviously they all say the speed should be set after cocking the shutter.
Anyway, there's another reason why damaged FEDs and Zorkis may be around but it's nothing to do with QC at the factory.
BTW, the first FEDs appeared in the UK in the 1940's when 1 or 2 came back from the USSR with visiting servicemen. They were rare enough to get a few pages of description and photographs in magazines at the time, plus a follow up letter saying how nice an RAF man thought his one was and in some ways better than a Leica.
Regards, David
PS Look at any make of camera for sale on line and you'll be amazed how few are sold with manuals. It makes me wonder if they were ever used and might account for the abuse some makes get from later owners.