Russian movement/case codes come in a ABCDE/FGHIJKH format.

AB = movement diametre in mm

CD, CDE = Soviet movement specification
see table at bottom of page

FGH = case variation

I = case material
Examples below from Vostok

0: stainless steel and other metals without plating
1: chrome plated
2: gold plated
3: gilded (at least 5 microns)
4: colour coated
5: synthetic, polymer, rubber
9: glass, crystal, ceramics, marble

JKH = Hand set

As a consequence of this system there's a 2416 Slava, 2416 Vostok & a 2416 Poljot movement that bear no similarity to each other, except that they match the 2416 specification (automatic, central second hand, shock protected & date plus all are 24mm in diametre).

Ontop of which there's 2 different Poljot 2616 movements that bare no relation to each other, except that they match the Soviet 2616 specification ( automatic, central second hand, shock protected & date plus both are 26mm in diametre). One's the 30 jewel job that's not uncommonly seen in Sekondas from 30 odd years ago, while the other's the the 23 jewel movement that one found in Buran Automats up until very recently.

As you can see above, from the orientation of the balance cock to the crown (on the left in both images above), these movements have nothing in common except their size & outward functionality.

Soviet, Russian and Belorussian Movement Codes Table
Notes:
- The standard movements codes were etablished in the Soviet Union on the early 1960s. Some codes may have been included in provision for movements which were never actually created.
- New Russian movements with new designations are still being created since the end of the USSR, and have been included in this table on the assumption that a central standard still exists.
- Not all post-Soviet movement codes conform to the standard e.g. Vostok 2433 is not a chronograph.
- The information displayed here has been gathered from a wide variety of sources, of varying accuracy. Italics have been used to indicate records where some uncertainty exists.
- As usual, this is a work in progress.