Thank you for your feedback. I appreciate the clarification regarding the standard production methods for the 1992-1993 Russian issues.
However, my goal is to document this specific 'sandwich effect' as a significant technological variety of the transition period. While it is true that many coins from this era show a visible core, the specimens in my collection exhibit a particularly prominent edge plating exposure (blanking error).
In numismatics, specifically in 'error and variety' collecting, this is categorized as a planchet-level defect because the protective plating was applied to the sheet prior to punching out the blanks, leaving the vertical edges completely unprotected and prone to oxidation.
What makes my study unique is that I have documented this consistent 'error' across:
1. Multiple Denominations: Both 5 and 50 Rubles.
2. Both Mints: Leningrad (LMD) and Moscow (MMD).
3. Chronological Transition: Comparing these magnetic steel 'sandwich' coins with my 10 specimens of the non-magnetic 1993 LMD 50 Rubles (Aluminum-Bronze), which feature a solid composition and an interrupted reeded edge.
While individual circulated coins might have low market value, a systematic set that proves the failure of edge-plating quality control across different years and mints holds significant educational and numismatic value for those studying post-Soviet minting history.
I am looking for specialists who categorize these as 'uncovered edge varieties' rather than just common circulation wear.