I've made patchbox releases that worked flawlessly, and then I've made some that were a constant pain in the neck. Recently I was restoring an original, 1820's period York County rifle, when I had to do some wood work on the toe of the gun. When I removed the toe plate, I noticed that even though the patchbox release pin was heavily rusted, the patchbox still worked well. A closer look revealed why.
The gunsmith had drilled his hole in the toe of the stock for the pin, and then sleeved it with a small piece of copper tubing. The tubing was driven into the hole and the pin then easily slid inside of it without binding. One last touch the gunsmith did to make it work without a hitch, was to drill a small hole in the patchbox spring where the pin would normally touch it, and then he filed the tip of the pin down so that it fit into the hole. Once in place, the pin couldn't slide off the spring and would never be affected by binding in the stock.
I had never seen this type of arrangement before, but it was so simple and worked so well, I thought some of the modern day builders might want to give it a try. It just goes to show you that the old boys really knew what they were doing, after over 190 years, the patchbox on this gun still worked perfectly.
FK