Bulge question

[Garth Gustafson]

I've attached some photos. This is a 16 ga O frame. Apologize for the quality. The hammer marks are faint and shallow and there is no perceptible bulge. You need to really look hard to see the hammer marks in the pattern. But you can feel them. Barrels are concentric and both barrels swamp in equally. Wall thickness measurements .078-.067 were taken in front of the forcing cone. Thanks for your comments, Garth

[Drew Hause]

Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives (C.I.P) http://www.cip-bobp.org/
Standard CIP proof pressure of 850 kg per sq. cm. (BAR) = 13,920 psi for a service pressure of 10,730 psi
Shotgun recommended minimum wall thickness (p.4) for “Standard Steel” with tensile strength = 101,526-123,137 psi
http://www.cip-bobp.org/sites/defaul...e/A-4-1_EN.pdf
10 & 12g........................20g
End of chamber - .079”.....075”
4” from breech - .075”.....071”
8” - .043”........................041”
12” - .030”......................028”

The Hunter's Encyclopedia, Raymond R. Camp Editor
From the German proof house: minimal wall thickness at the end of chamber, regardless of length, for 12, 16 & 20 gauge guns should be 2.3mm (.0906”) for “Ordinary Good Steel”

The tensile strength of your crolle damascus barrel is about 55,000 psi - 1/2 of CIPs "standard steel". I would use your gun only with full length subgauge tubes which to my knowledge no one makes in 16g. I am sorry.