Mine was a revolver. Astra 680: it was recently discussed in a thread. The cause was dead simple: grit and powder residue build up on the flat crane-to-frame mating surface.
However, until it was identified the revolver was useless: impossible to pull back the trigger.
One wipe and I was back in business!
You cannot wake someone who is pretending to sleep. Stop pretending. Wake up.
Doubt: ...it's the only thing I'm sure of...
-Marsupials: Nature's idea of Concealed-Carry-