Making the new tumblers, they are made from 1095 and heat treated for maximum wear resistance.
The new left and right tumblers, The blue lines indicate the difference in the shape of the spring bearing surface. The new tumblers keep the springs cramped up until the over-center (trip) point is reached, thus imparting the spring's full stored energy into the tumbler at the point of release.
I also made a new tumbler pivot, since the original was distorted. I also enlarged the threaded portion to the same diameter as the shank for added strength, and drilled and tapped the forend iron to match.
The parts ready for final assembly,
The forend iron assembly ready to be put back into the wood, the gun now ejects the empties cleanly over the shooter's shoulder.