Spring back will be anywhere from 0 to 50%.....it's a good idea to keep the heat on after the bend, as Brent said, and it's important to let the stock cool completely. Once you have a stock thoroughly heated and you've applied pressure to bend it, you can release the pressure and see how far it returns; then bend it back once again...enough "experience" observing the spring back when hot will help you learn what to expect once a stock has cooled...when doing an extreme bend (especially when altering drop), I sometimes like to just turn the heat back on after the stock has cooled overnight and heat it for another hour with the clamps in place....be careful when refiting trigger guards in straight stocks....the English had a habit of hardening long guards, probably to provide extra strength to the wrist....if hardened, they can be broken.....
