Tough to diagnose this problem w/o seeing the gun. With the lock screws tightened , can you hear , feel the full cock and safety notch position? First ,........ remove the lock and put some inletting black on the end of the sear arm and reinstall the lock , tighten screws normally , and tap the lock face lightly to seat the lock into the lock mortise. Remove the lock , and look for the tell tale black smudge of the end of the sear arm inside the bottom of the sear hole in the mortise. Do the same test for the sear arm , after trying to cock the gunlock. Any sign of a smudge from the inletting black , wood should be removed. Second......Put some inletting black on top of the curve of the main spring , do the same test. Reassemble , tap , and cycle the lock , look for a smudge. Remove offending wood. .........Next , we look at the lock function. Remove the lock Work the lock through the safety , half cock position ,put a drop of light oil on the fly , make sure it flips, when the lock is cycled to full cock ,and make sure the sear seats firmly into the firing notch. All these mechanical functions are visible to the eye and can be studied to ascertain the lock is working as intended. If you aren't comfortable working on the mechanical parts , it's best to take or send it to someone qualified to fix it. This whole problem is a major SAFETY issue. If when assembled , the trigger has no detectable play in the full cock position , The top of the trigger may have to have a tiny bit of clearance ground from the top where the sear arm touches the top of the trigger. Never do this until the lock mechanism , and wood fit is examined first. Questions? ..................oldwood
