The throat is a barrel or cylinder dimension, or both. Obviously if the cartridge can be loaded into a cylinder and closed it isn't a case dimension issue. Cases don't encroach on the barrel throat, bullets do that. In the case of a revolver, if the bullets were actually causing a problem with the barrel throat, the out-of-spec OAL wouldn't allow the cylinder to turn because bullets would be jamming against the barrel forcing cone. You may be forgetting that a revolver cylinder is the chamber unlike a rifle or pistol.
I have experience with that using a 625. Ammo over the OAL due to bullet creep will lock the cylinder up tight. They simply can't be fired.
How does that happen? The OAL is within spec when the cyl is closed. Firing the revolver pulls the bullet and OAL becomes too long which locks the cyl.