Gene: I assume (hope) you mean .050 - .060 "around" 6 - 8 inches

C.I.P. recommended wall thickness for 12g proved at 850 kg per sq. cm. (BAR) = 13,920 psi for a service pressure of 10,730 psi for Category 1 “Standard Steel” (Non-alloy AISI 1045) with tensile strength = 101,526-123,137 psi
End of chamber - .079”
4” from breech - .075”
8” - .043”

Category 1 would fit the industry standards for 4140 Chrome Moly & 4340 Chrome Moly Nickel - both are “low alloy” steel and about twice the tensile strength of crolle damascus

For a pattern welded barrel I would want .105" at the end of the chamber and .045 at 9"

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