Hello Palunc,
Here is part of an article that Michael Orlen wrote for "American Gunsmith"
magazine:
You are going to find that some gunstocks bend much more easily than
others. American Black Walnut cannot be bent as easily or as far as English
or European walnuts. I have seen some American Walnut stocks that simply
would not bend and some English Walnut stocks that bent so well that drastic
changes in drop (up to 1”) were easily done with little if any spring back.
When a large change in drop is required, I often like to do it in two
sessions with a few days between. This may be just superstition, but doing
half of the bend at a time seems to make the process easier and lessens the
spring back.
I think it answers your question.
JC