Book excerpt: A step by step walk through of building a percussion lock from scratch using only tools commonly found in a home workshop, and easily obtained materials. The lock is built and designed at the same time, allowing each part to define where the next part fits, and how it looks. Using this build process, it should be possible to modify this lock design to fit any size or style muzzle loading gun. From plain materials to case hardening, the entire process is described in text and in full color pictures.