Watertable

[chiefnpd]

Where did the reference to a watertable on a shotgun come from? In other words why is is called a watertable?
Thanks,
JC

[Dutch Henry]

Watertable - The top of the bar of the action, the flat projection on the front of the receiver of a side-by-side gun, perpendicular to the standing breech. The cocking arms, hingepin and locking bolts are typically mounted inside the bar, below the watertable. The Table, or the Action Flat. The reference is lost in obscurity.

From: http://www.hallowellco.com/abbrevia.htm