Replying to Datchery. I hope I have quoted the question <modsnip>
The weapon is a historic design -- not F Lee Pieta as stated, but F.LLI Pietta (not that it matters because the answer to your question is the same).
This is a single-action revolver. That means that it is not fired simply by pulling (squeezing) the triggere! The revolver must first be "cocked" by drawing the hammer back (usually with the thumb of the operating hand) to what is called a "full *advertiser censored*" position. The reason that is important is that the hammer can be drawn back to a half-*advertiser censored* position. It is in the half-*advertiser censored* condition that the weapon is loaded or unloaded or inspected. See note about "going off half-cocked" below.
The round thing (which has been wrongly referred to here as a "drum") is called the "cylinder" and it is in the cylinder that the rounds/bullets are loaded. Unlike modern double-action revolvers, the cylinder does NOT swing out for loading/unloading/inspection. Rather, you can see on the side of the weapon (usually on the right side) just to the rear of the cylinder a "loading gate" which swings away from the frame and allows access to the rear of the cylinder --- ONE CHAMBER AT A TIME!! -- THIS IS IMPORTANT!)
In order to open the loading gate, the hammer must be in the half-*advertiser censored* position. When the hammer is at half-*advertiser censored*, the trigger is blocked and the weapon cannot be discharged. While at half-*advertiser censored* with the loading gate open, the cylinder may be rotated so that each chamber may be inspected, unloaded or loaded. On the same side as the loading gate, there is a rod attached to the frame just forward of the cylinder and the rod is held in position by a spring. The operator may slide the rod to the rear of the frame whereupon it will enter the front end of the cylinder and push through the cylinder thus removing any casing or bullet that is in that perticular chamber of the cylinder. The rod is then released so that the cylinder may be rotated to the next position and similarly cleared/unloaded.
Typically, these revolvers have six chambers (hence the term "six-shooter") but may have only five or, in the case of .22 cal. revolvers, may have as many as nine chambers. Revolvers chambered for .45 Long Colt will not have more than six chambers because the rounds/bullets are too large (almost half an inch in diameter).
Okay; so How do you check the weapon?
I am not familiar enough with the F.LLI Pietta design to know for certain, but I base my answer on the Ruger Single-six which you can examine safely at any gun store where the clerk will have an unloaded weapon in his showcase and will be happy to demonstrate all the above and below. Make him think you are interested in buying because he is not going to respond well to "Oh, I was thinking about the homicide on the movie set . . . . Do not ask to see a F.LLI Pietta because he is not going to have one and he will immediately know why you are there! Ask to see a Ruger Single-six in any caliber like .357 or .44. Don't ask for .45 Long Colt because he may not stock that one.
The most reasonable way to check a single-action revolver for safe condition is to unload it by going to half-*advertiser censored*, opening the loading gate, and using the clearing rod to unload each chamber. Then you can observe the rear of the cylinder as you rotate it (it will turn freely and may or may not have little "click" detents during rotation) and assure that all the chambers are empty. THEN you would load whatever you wish to put into each of the chambers -- or only one or two of them. When that is conccluded, you would close the loading gate and release the hammer -- or just leave it at half-*advertiser censored*.
To fire the weapon, draw the hammer back to the full-cocked position, aim and squeeze the trigger. After the weapon has discharged (or not if you had it set to an empty chamber), nothing will happen until you draw the hammer back to the full cocked position which will cause the cylinder to rotate one increment thus placing the next chamber in position.
To "Safe the weapon" point the barrel to a safe place (not the sky!) away from people and things, hold the hammer securely and squeeze the trigger and SLOWLY lower the hammer. Best place to leave the hammer is at half-*advertiser censored*.
GOING OFF HALF-COCKED
While you are looking at that Ruger Single-Six, ask the clerk about the "Transfer Bar." (The F.LLI Pietta almost surely did not have a transfer bar!)
A single-action revolver which is loaded and fully cocked might be dropped and the impact jolt could release the "sear" which holds the hammer in position. That would allow the hammer to swing forward and strike the bullet and discharge the weapon which could be aimed anywhere at that time. This is often seen in old Western movies and usually the bullet will hit a chandelier and the fixture will fall onto a table or onto a bad guy, etc. If you're old enough, you've seen such a movie. Always in black and white.
Such weapons COULD have the same thing happen if only half-cocked when dropped. That is always what we call "bad ****."
The weapon is said to have "gone off half-cocked."
TRANSFER BAR (circa 1972?)
Rules made in the early seventies required that a half-cocked or fully cocked revolver could not discharge unless the operator was squeezing the trigger while the hammer fell onto the ammunition/bullet.
As the trigger is squeezed, a bar moves up into a position between the hammer and the firing pin. The hammer strikes the transfer bar which, in turn, strikes the firing pin. The hammer has a lug above the place where the transfer bar will be such that IF the transfer bar is not in position, the hammer will strike the frame of the revolver above (usually) the firing pin and the firing pin will not move --- thus the weapon will not discharge.
The Ruger Single-six you are looking at will have a transfer bar and you will be able to observe what happens if you .... Well, just get the clerk to show you. It would be very difficult for me to explain without a video or series of pictures.
ANYWAY -- IN CONCLUSION
A.B. <modsnip> I would not expect him to know how to properly inspect the single-action revolver. That is why the movie company has an armorer and why it is reasonable to say that A.B. should have been able to rely on the "unloaded" weapon assurance when the weapon was handed to him. Whether the A.D. should have been allowed to handle the weapon between the armorer's preparation is a question for someone else.
THE QUICK CHECK we are taught to use with double-action revolvers does NOT APPLY to single-action revolvers. I don't happen to like A.B., but he is being criticized for not checking the weapon and l submit that he could NOT have been expected to know how to do that. I would have been expected to know how to do it because I am a self-confessed "gun nut."
I hope that helps somebody.
C