Appalachian Barn Gun Kit (Percussion) — Step 4: Wood Clearance for the Lock’s Moving Parts

After the lock fits in place, coat the entire internal lock surface with a very thin layer of transfer color (Prussian blue, inletting black, candle soot, or similar). Use the lock bolt to pull the lock fully into place, then cycle the lock from rest, to half cock, to full cock. Remove the lock, being careful to keep your fingers out of the path of the hammer should the lock trip while being removed, and lower the hammer to the rest position once it is out.

Inspect the wood for any areas where the transfer color shows that the moving internal parts of the lock have touched the wood. Scrape or trim any such wood away with a chisel, gouge, or scraper, paying particular attention to the hole the sear arm extends into. Wood interference can prevent the lock from functioning properly. Repeat until there is absolutely no wood interference with the lock’s moving parts.