Next, have a clear loading table in front of you with only six rounds, carefully inspected to be blanks, and load each in turn through the gate. The loader may or may not leave an empty chamber under the hammer.
For loading dummy rounds, inspect each chamber, and then load each with dummy rounds. Point the gun at the ground, (and if you are Dr Fauci at a small dog,) then full cock and drop the hammer on each chamber.
There may be different procedures if the cylinder is pulled to load.
I would expect that the load for a shot at the camera, these days, would be 5 dummies and 1 properly positioned blank. With the high resolution today’s movie-viewers expect, the dummies have to be there. The blank will give all the reality you need without stupid CGI.
With this kind of load, the actor could not realistically check without ruining the shot.
Baldwin was, no-doubt, lazy. For a rehearsal with what should have been empty or all dummies, he could check - click, click, click 6 times.
Of course, anyone there watching would know how he operates, and there is the final, filmed shot, where as I said, I don’t think he can check.