Here is Bill's second post:
2) Inadequate cock throw:
As made, the cock throw was adequate only for a percussion system. At half cock, even a short flint rested on the frizzen face, preventing its closure on the pan. At full cock, the cock barely developed enough momentum to strike good sparks and throw the frizzen forward, even with a strengthened spring. The first two photos show the “as built” cocking positions.
Grinding away at the tumbler and bridle (where they contacted each other to limit the backward pull of the cock) helped, and additionally the top of the sear had to be relieved to clear the new downward depression of the mainspring as the cock traveled farther back.
A new long nosed sear was installed (a new L and R part from another lock type) to reach the notches of the tumbler. The bridle needed further modifications for the new sear. In the new tumbler position, the existing full cock notch was at the wrong angle and would not hold at full cock. I sent the lock to Dave Person again, and he annealed the tumbler, re-cut the notch to the correct angle, and re-hardened it. The lock now had a flintlock degree of throw and sparked well.
However, upon replacing the lock in the stock, the cock wouldn’t pull back far enough to engage the sear at full cock. The trouble was interference of the forward part of the tumbler on the swivel axel washer. Grinding on the tumbler corrected that. Now the back of the cock gooseneck ran into the stock, which had to be notched to accommodate the new cock position. The second two photos show the corrected half and full cock positions. Note the (yet unstained) notch in the stock to accommodate the new full cock position. (This notch is often seen on original single and double barreled Kentucky rifles.)
Bill Paton