I had my Smith and Wesson Model 27, .357 revolver out last night for a good internal cleaning before I begin a summer of intense practice leading up to deer season. I removed the side plate screws and removed the crane and cylinder and began tapping the grip frame with a rubber mallet to drop the closely-fitted side plate into my hand. As the plate released, I bobbled the works and the plate went tumbling across the carpet, landing a about 18" from my feet. I set the pistol down on a large white cloth I use for such operations and picked up the side plate. A small part called the hammer block rides in the plate in a groove. It is about 1.5" long, "L" shaped, with a flattened area at 90 degrees to the bend which is slotted to ride on a pin in the action. It's not a big part, but it's black and certainly big enough to see on a beige, close weaved carpet, yet I never found it. I looked for an hour wondering if it had fallen through a hole in the universe. I searched everywhere and never found it. My conclusion? It was never there to begin with. Now, how the devil I came up missing, and when, is beyond me. The gun will function fine with out it (tho a little less safe should a sledge hammer hit the back end of the hammer) and would never have noticed it's lack. I have been working on S&W's for almost 35 years and have never put one back together without the hammerblock.
Weird. I had to share with someone...~Muir
PS: Ordered another hammer block last night.