Barrel Wall Thickness Gauge


The gauge, alone.                                                                               The gauge, measuring a set of shotgun barrels.

A shotgun's barrel wall thickness can be measured at nearly any point, between the probe of the dial gauge and the bead at the top of either of the rods, searching for the thinnest point. For stiffness and accuracy of reading, one should use the thickest rod allowable by the size of the bore.

Barrel Wall Thickness - The thickness of the walls of a shotgun barrel tube. It is reasonable to assume that guns built by responsible manufacturers are safe to shoot, when new, with the loads for which they were intended. As the decades go by, however, as barrels are drawfiled or buffed for rebluing and as occasional pits are honed out of the bores, steel is gradually removed from the barrels. The barrel walls, already built thin for lightness, become thinner still. At some point they become too thin for safety. It is important to know the minimum barrel wall thickness of an old, well-used shotgun before shooting it. While there are many other variables---loads to be shot, barrel steel composition, heat treatment, age, dents & rivells, tightness of choke, altered forcing cones, quality of original manufacture---and there is no substitute for an actual proof test, a useful rule of thumb states that provided the gun in question is otherwise in sound condition, the minimum barrel wall thickness should be .020" in a 12 gauge gun. Smaller bores, with higher pressures should be somewhat thicker.



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