Still trying to restock my #4. The fore stock went fine as did the butt. However, the stock bolt channel is about 1/2 inch too short and the bolt will not catch. My other never installed butt has the same short measurement. There is a metal washer at the bottom of the channel I never knew existed until now. I tried to hook it out with heavy wire but it didn't work. How do I go about fixing this? Every other stock swap in my past was with previously installed wood so I had no idea what I was getting into. Any help will be appreciated.