When you dry fire the action on a block of wood,,do each of the imprints of the separate firing pins show about the same depth in the wood?
Or does the Left bbl show a shallow depth compared to the RH side.
They may protrude from the action face the same,,but if the LH is hanging up, stalling for some reason, or a weak spring, a shallow imprint compared to the 'good bbl' will usually show up.
Someone may have shortened the spring a bit in order to reassemble the gun.
They can be a bear to reassemble if you are unfamiliar with them. Easy if you are familiar with the process. There is even a small tool to pull the spring back (compress it) so the front end
components can be installed easily. Then the hammers can be dropped into place by putting the bbls and FE on the frame and opening the gun a ways. No struggling with springs.
Unaware of these things people start struggling with the powerful hammer spring(s). A couple coils clipped off will make
re-assembly much easier using the 'muscle it into position' method of assembly.
But that doesn't help with reliability.
Just some thoughts.
