1911Tuner
Moderator Emeritus
I certainly can't tell from that video when the bullet exits and any perceptible slide recoil happens.
Brother...If ya can't see it, it's because you refuse to see it. In the very last one...before the snub revolver...slide movement is clearly seen even before the initial blowby gasses escape.
If the bullet is gone before the slide moves, the slide won't move...at least not very much. While the exiting gasses and burned particulate have mass...it's not much mass. It's equal to the mass of the unburned powder charge. In the typical .45 ACP cartridge...that's about 5 grains. Even at a theoretical 4,000 fps exit velocity...which I think is pretty fanciful...that would amount to about 1/5th the recoil impulse generated by a standard velocity .22 Short. Not nearly enough to move the slide with the force and at the speeds that occur during the cycle.
The theories that you offered are impressive...and I'm not being facetious when I say that. I'd have accepted it if I didn't already know better, but you're making this thing way more complicated than it is. Recoil...and recoil operated...is nothing more (complex) than Newton's 3rd Law.
If the forces imposed in an action/reaction system are great enough to set both sides of the system in motion...they'll both move at the same instant. They don't have a choice.