So, that's of no use either. But then, there's this, and it's a gem. It gives us a bird's eye view.
Ed Chiarini made this, and I am not interested in his views. I am only interested in the footage.
And what it shows is no muzzle flash.
That's it. He's firing. In the next frame or two, we are going to see Oswald grimace from having been shot.
There. Oswald has been shot. He is reacting to it right there. That pained look on his face, that grimace, that's from being shot. But, we were watching the whole time with a bird's eye view. How could we possibly have missed the muzzle flash?
And, of course, it just continues from there. Oswald has been shot. But, we never saw any muzzle flash. Look, he's going down:
Oswald was shot shot, but we never saw any muzzle flash.
The muzzle flash from a blank is usually only slight, although it doesn't have to be. In making movies, they will pack extra gunpowder in with the blank to create as much muzzle flash as with a live round. But, in this case, we'll assume they didn't do that.
But, there's more involved than just muzzle flash. Remember that when a revolver is fired, that a visible effect occurs not just at the muzzle but at the cylinder gap. The cylinder gap is the space between the cylinder and the forcing cone.
There needs to be a gap there because the cylinder has to be able to rotate. But besides that, although most of the gases expand into the barrel and come out the muzzle, some gases escape through the cylinder gap. Quite a lot of gases can escape through the cylinder gap.
Here is a picture of 357 which is very similar and comparable to a 38 Special, like the one "Ruby" supposedly fired:
You can see how similar that revolver looks to Ruby's Colt Cobra Special:
So, don't you think that when the Shooter pulled the trigger at this point in time that we should have seen something?
And I take that as evidence that he definitely did NOT fire a live round.