Smoothbore project - repro cast sear spring shaping/tempering
My original H&P shoots very well, but has a horrendous trigger pull. I have managed to get the pull to a barely useable 7 pounds by adding a shim to the tumbler. I want to get the pull down to a competition value somewhere in the 3.5-5 lb range. Next step was to shorten the sear spring. But rather than touch the original sear spring, I ordered a repro - but it came as-cast, so needs to be fitted/shaped.
My question for you metal workers out there - please check my procedure - I am rank amateur at metal working, so would like advice to ensure I have it correct before I begin. Did some basic Google research -
1. Annealing - I assume I need to anneal it before I begin to shape it or it will be too hard to file? Do I do this by heating cherry red and letting air cool? Or can I start shaping it as-cast?
2. Shaping - using a file to get it to fit the lock, ensuring final shaping using a fine/draw file to remove filing marks, keeping strokes always lengthwise to the spring.
3. Hardening - heat cherry red, then quench in oil.
4. Tempering - heat to blue/purple, then quench in oil.
Comments/advice appreciated.
Tom Magno, 9269V
29th Wisconsin Volunteer Infantry
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