>
> Any similar experiences, comments, or theories?
>

I have a winged corker not a floor model, I find that it is
very sensitive to the stiffness of the corks. I've bottled
with dry #9 corks and even after a dousing in boiling water
they tend to leave mushroom heads. Then I started storing
my corks in a potassium meta humidor and that seems to have
solved the problem. I assume it was the long term storage in
high humidity making the corks softer.

Don