Get the lead out.

[Kensal Rise]

While I have been hesitant to join this discussion, I thought I'd offer a few perspectives of my own:

Lead oxide isn't good. But it may not be the only factor involved in this issue. Certain lead alloys seem to oxidize to different degrees. And under different conditions.

Then there is the stock wood. As mentioned, some of it is naturally acidic. Some less so. Some may absorb more moisture than other pieces. What's more, figured wood seems to be less resistant to strain/cracking/checking than more plain wood. American black Walnut is more prone to this than English/French walnut.

Then there is the gun's environment to consider. Was it kept in a humid climate? A very dry climate? Was it used in bad weather conditions where moisture could be an issue with the wood and lead oxidation?

Or... is the gun just OLD. Wood does not last forever. Some seems to. Other stocks fail before their time.

My only point is that lead in a butt stock for balance is just ONE factor in a gunstock's endurance or failure.