A while back, I picked up an unknown condition Moskva 5 for peanuts. It showed up, and the little flip out rf mech/prisms had a good deal of slop/backlash in the gears between the front lens cell and the prisms themselves. One could rotate the lens a few degrees before any movement in the prisms and RF would occur. If I recall, the backlash was caused by a hole bored through the middle of a gear being a few thousandths of an inch too large for the post it rotates on.
Last week I bought another for peanuts, this one slightly earlier than the previous. Got it today, exact same deal, exact same amount of slop.
Let's save the soviet manufacturing and QC comments...I've got a Jupiter 9 from KMZ that predates this moskva by a year, and the build and finish is top notch. I also have later KMZ gear that is just fine, too...it seems like these Moskvas just inherently have the slop? Did the Super Ikontas have this problem, too? I'm going to throw a piece of ground glass in the back and see if the slop makes a real difference (or if focusing from one direction or another makes a difference), but it is kind of annoying to have it there.