I recently had to remove a lock from an old gun. The mainspring broke a long time ago and there is rust on the fracture point on the two pieces. A rubber strip was found placed between them and I suspect the gunsmith used the rubber to provide tension should the spring break (which it eventually did at some point before)? That the spring broke mean the hammer couldn't be rotated forward (no spring tension to rotate the tumbler and with the tumbler, the hammer).
Thoughts on the rubber piece?
