Maybe if Churchill had consulted Major Sir Gerald Burrard, he too would have know what the table/watertable would have been. The watertable, table albeit without the adjective water, is defined as the thickness of the top of the frame left after milling. If you look toward the reciever, then it does look like a table or picnic table. In a boxlock the mainspring is pressed aganist the lower side of the watertable. A sidelock has the thickest watertable followed by the bar action sidelock then the boxlock. In "The Modern Shotgun" by Burrard Volume 1 at page yo will find "The "table" of the action, which is the part submitted to a tensile strain on firing;....." and it is mentioned as well as defined pictorially on pages 74-78. The term action flats seems to have originated with the British and I think is centered around the fact that the craftsman that actually does the work is an actioner. So if the action is referred to as a frame would the craftsman be a framer or if the piece of metal is called a receiver would the finisher be a receiverer??? Without a doubt the top of the frame/receiver is defined as a table and I guess that the water term was attached either in manufacturing, or checking the plane, or I think it was McIntosh that offered the association that it was a location where water would catch in a rainy day. But the true English sportsman wouldn't be caught chasing quarry in inclement weather.
Most, if not all, consider Burrard to be a far cry from the fount of a wives' tale.
I believe the French refer to it as "La table de la bascule", but someone correct me if incorrect.
Kind Regards,
Raimey
rse