""the forward thrust is resolved by the hinge pin alone.""
Certainly not on all guns. A well fitted cross bolt or doll's head shares the load as does the front face of the rear lug on a double under-bolted gun. It is certaijnly stretching things a LOOONG way to claim there is rotational movement of the hinge during firing, with the gun bolted shut.
Some years ago an Uncle of mine was wanting about a 70HP tractor. He found one a dealer had sold, then taken back because the first owner decided he needed a larger one for his use. It was hardly broken in & the dealer offered my uncle a very good deal on it with a full warranty. After putting about 100 hrs on it he couldn't keep oil in it, called the dealer. They came & picked it up. Found a little rubber hose had been left off at the factory which connected the air cleaner to the intake. Rings were eaten up, the dust/grit had imbedded into the cast iron cylinder sleeve & devoured them. Be hard to convince him this could only happen with a "WATER" based carrier.
