A casual observation that I have made is that - regarding the depth of the water table - on a double rifle there appears to be as much depth above the bar (diameters of barrels) as there is below the bar (from water table to bottom of action).

Along with adding more strength to the action it would also serve the purpose of adding weight to the action "between the hands".

This would particularly be the case with large calibre doubles - with large calibre barrels - and the need for strength and recoil absorbing weight. Larger diameters around chambers would add depth to bar if increased proportionally to the chamber area of the barrels.

Would their also be a correlation between length of cartridge/pressures and water table length ???

Along with weight and pressure resisting dimensions increasing the size (depth and length) of the bar would add proportion to the gun.

What say ye ???

PUgwash, All of what you says makes perfect sense and your contribution is appreciated. Weight is added in order to resist stresses in critical areas - elbow and face of action along with depth and length of water table - and to add weight without compromising balance/handlabilty.

I have seen templates used to determine particular shapes on actions and stocks but have never seen - perhaps not recognised - templates for determining the dimensions of double rifles. Now that scaling actions to suit calibre is becoming more "refined" (??) there would be proportions that the gunmakers use for strength, aesthetics, appropriate weight and dynamic handling.