I believe it is as Dean and some others have said. Moisture over time corrodes lead into lead oxide or lead carbonate. This is less dense than lead itself and increases the volume as corrosion occurs. In time this will split the wood. I am no chemist, but after 100 years I would think that even the low moisture content of the wood itself would be enough to do this. Of course many guns have their wood exposed to considerable moisture helping the process along. It does not happen overnight.
|