"The R51 sequence is correct but fails to demonstrate how the breechblock kicks the slide back and gives it the momentum to pull the breechblock upward and draw it back as the slide moves back."
They both initially recoil together as a unit, before the block is halted. That's the official Remington animation, so I suspect it's accurate (if only their machining was...)
"The slide does not begin to move till the bullet leaves the barrel. The barrel does not begin to drop till the bullet leaves the barrel. Locked breech."
Criminy. We go through this 'debate' on the forum at least once a fortnight. By what mechanism of physics would the barrel/slide breech assembly not recoil some tiny amount as the bullet translates? I think we found through calculations it was like .03" or something tiny like that, but was reached so quickly that the slide had all the momentum it needed to cycle.
"If it were otherwise accuracy would not be dependable."
If you run the numbers, that small initial deflection translates to thousandths of an inch of change to the barrel orientation, and is also very predictable/repeatable. Probably contributes to different POI for different loads, but only a little.
Video 1 is too fast for this purpose
Video 2 clearly shows the barrel/slide moving (or do you think a 1,000,000 fps camera would be trained on a gun in someone's hands? That stuff is expensive and very short duration; the gun was fired from a fixture.
Video 3 less clearly shows the barrel/slide moving before the flash of the bullet escaping (looked like .05" or so)
Video 4 has too much motion blur to tell much
Now, does a small bit of blow-by of gas start leaking from the muzzle before detectable motion of the slide has occurred? Yes.
TCB
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