Your original revolver checkout article has always been a useful tool in buying used revolvers. Whenever I am interested in a used revolver I begin by asking the sales clerk "do you know how to check out a revolver?" and then showing them how. You receive the credit.
Best purchase was a S&W Model 15 Combat Masterpiece that suffered a botched trigger job and was unsafe. Your checkout revealed the problem that resulted in buying the Smith for next to nothing. A replacement trigger and hammer group returned the Smith to like new operation. Similar situation with a S&W 629.