Third gun from around this era that has the jacked up stock near the buttplate. I don’t think it’s water damage because the buttokate screws aren’t rusty and it sands right off.
I see only two possibilities. Assuming that the varnish was cracked and perhaps peeling a bit, I would say that mould growth on the wood or the wood was stained by the dirt or the soil from a hunting adventure.
You might be on to something Bill. Those plates have to have some sort of dye or pigment added to them
The oil finish was used only on the first years. What year is your shotgun? Regarding the buttplate, It is the first time I have heard about dying horn??
This is my 1939. I have no idea if they dyed them or not but I would think that horn isn’t black throughout
I just looked at one I have that’s broken in half. If they are dyed it’s all the way through. This one has some gouges in it and it’s black in them too