Totally agree on that Shotgunlover.
I'd love to see such footage.
Many people have argued aboud third bites and their construction and that is based on one's understanding of the physics, not real data.
The people who have some real experience are the one who made long lasting shotguns & double rifles that were shot a lot and whom staid in business for a long time.
Westley-R comes to mind as an example.

There are usually two ideas behind the 3rd bite.
- the first one is to keep the gun shut (Purdey et al.)
- the other one is to keep the action from flexing under the backward force at the breech. This is a clear fact of life as otherwise nobody would be rounding the action root.
The old doll's head without bite only tries to address this second phenomenon.

Some third bites do both: Greener (not the best), Webley screw grips ,Rigby Bissell Rising bite ,Ideal , Westley Richards C bolt, etc.

Of course, the best doubles to investigate this phenomenon are not shotties, but double rifles.

Best regards,
WC-