Pigeon shooting expert
Im not sure if pouring cold water down the barrels is a good idea! Getting water near the barrels in any situation is generally a bad idea.
Most semi-autos and over-unders have ventilated ribs on their barrels, and these definitely help dissipate the heat and cool them down.
If the sport on your laid wheat was that fast and furious, a bit of heat haze was probably a small price to pay.