Not quite on the topic at hand, but an old friend of mine used to mention that he worked summers, between college semesters, for William Crites who ran a gun shop in San Antonio, Texas in the late 1920s and early 1930s. He said that whenever top break revolvers were brought in for repair, the old man would wait until the customer exited the shop, open the revolver and rap it smartly against his work bench until the latch would lock tightly again and pronounce it "fixed."