Only trick I know to try is heat, that will usually loosen it when nothing else will. If you have a propane or butane (better cause it gets hotter) torch, try that. Use with caution and good luck buddy!
NOTE: do not use around fiberglass!!!!
I have had several sets and have always been happy with the price & quality- one of my recent acquisitions came with this set as well as the original stocks....
I understand Steve, I know how it is when you've been injured and in pain. Sorry you couldn't make it yesterday, I did get to meet your son and told him to let you know I hoped you get to feeling better soon.
Regards, Jere