Only that last link provide a video, the others were all stills.
With the revolver if you go frame by frame you can catch the initial cavitation discharge of the water column exiting the barrel. I can only make an assumtion at this frame but IMO it's just after the bullet has exited the cylinder. If you jump between this frame (2:15) and the one immediately proceeding it (2:14) you'll see the barrel rises about 1/4 to 1/2 degree at this point. Unfortunately, the next frame (2:17) is post bullet exit from the barrel where the bullet can clearly be seen. At that point it is obvious that the muzzle has risen by at least 5 degrees.
Now consider that muzzle deflection between (2:14) and (2:15). While 1/4 degrees doesn't seem like a lot, that is a whopping 15 minutes of angle. This means the deflection in POI at 100 yards will be 15 INCHES. Divide 15 inches by 4 and you have a deflection of 3 3/4 inches as the bullet is ENTERING the barrel. While that sounds extreme, that is because the only thing restraining the gun is the flat base it's mounted to and the water enclosing the whole rig.
It's why I suggest that you try shooting from a rest with two consecutive rounds. One with the muzzle flip unrestrained and one with the muzzle flip restrained. I've done this as an experiment and have seen the results, the change in elevation is HUGE.
BTW, the reason I tried it was because I was having problems with consistent recoil management with my 6 1/2 inch 610 shooting 40 caliber ammunition. My thought was to let the mass of that long heavy barrel control the recoil, thus eliminating my recoil management issues. Only took me two shots to decide that was a dumb idea, sailed both rounds over the target in spite of aming at that very bottom of a 12 inch target. BTW, range was 25 yards. After that excercise I concluded that there just aren't any shortcuts to gaining consistent recoil management and put in two years of work with the 610 to get where I wanted to be. A side benefit of doing this is that I also got a lot better at shooting my shorter barreled handguns.
I'm also curious where you got that 0.97 ft.lbs. recoil energy number. Physics here again. According to the Law of Conservation of Energy, Energy In EQUALS Energy Out. Most 38 spl. range loads generate about 200 ft.lbs. of Muzzle Energy. That means that the total energy expressed by recoil will also be 200 ft.lbs. Now, it's been almost 40 years since I did any work with the SI system of units of measure but I still remember that one failing of the English system of measures is that in some cases the units used to describe a measurement can be VERY confusing. One of these confusions is that Energy is defined using the same units as Torque, the ft.lbs. However, they are not really the same units. It's an area where the Metric System, or SI is vastly superior, under SI energy is defined as Joules and torque is a Newton Meter. In addition, IIRC in the English system Work is also sometimes expressed as ft.lbs./S and sometimes as Horesepower. I suspect that 0.97 ft.lbs. number your are reporting is actually a unit of Work, not energy. IIRC it should also actually be ft.lbs./SECOND. Bascially, it's a unit of Mass being acted on by a Force over a period of Time. Forty years ago I could probably have done the calculations involved, unfortunately after 40 years I just have no idea where to even start. I also have a vague memory of a conversion factor of 32.2 feet per second being required to convert Lbs. Force to Lbs. Mass. Bottomline, the English system of units is a complete hash and drove me absolutely nuts trying to keep it straight when I was in Dynamics. What's sad is that I aced Dynamics, however if you don't use it you lose it. Back then I also took German and about all I can remember of German today is how to say hello or ask a girl to dance.
Finally, I would suggest that you stop poking around the internet trying to prove your point. The simple fact is that anything you find will be compressed too much to yield any real information. Frames will have been dropped during compression and those missing frames are nearly essential. In addition, you need videos shot with Lab Grade high speed cameras, 600 frames per second won't cut it when you need 60,000 frames per second to illustrate a high speed event like a gun firing. You're also flogging a dead horse. Barrel do move while the bullet is in the barrel, in some cases a lot. I still remember my father telling me that when a Battleship like the Missouri fired a full broadside with every gun it would shove the whole ship 3 feet sideways in the water.
