Damascus, Twisted and Laminated - same?

[Researcher]

Those tubes were proofed at the Birmingham Proof House, so not Parker Bros. made Laminated tubes, but tubes bought from a Birmingham supplier.

[BillCorn]

Originally Posted by Dave Noreen

Those tubes were proofed at the Birmingham Proof House, so not Parker Bros. made Laminated tubes, but tubes bought from a Birmingham supplier.

What does that mean for the strength of them?

[Drew Hause]

That would be an earlier form of English Laminated Steel than that tested in the 1891 Birmingham Proof House trial, but there is no reason to believe the strength would be less than other pattern welded tubes ie. about 55,000 psi
https://docs.google.com/document/d/1...U/edit?tab=t.0

A reminder
Tensile strength is only a part of the equation for estimating bursting pressure. If the barrel is made of Twist with a 50,000 psi tensile strength, that does NOT mean that it will withstand a 10,000 psi load by a factor of 5.

Barlow's formula P=2 S t / D
P=Bursting pressure in psi.
S=Tensile strength of material in tube wall.
t=Wall thickness in inches.
D=Outside diameter in inches.

Barlow's refers to a pipe capped at both ends with a static pressure (a pressure cylinder). Shotgun barrels are not designed to be pressure vessels as one end is open and the pressure rises and falls quickly.

It took about 30,000 psi for Sherman Bell to burst a Parker Vulcan Steel and a Parker D3 barrel

[Mike of the Mountain]

With sufficient wall thickness in our pattern welded guns, we shoot standard target loads at clays and game. At The Southern I shot my grade 2 top-lever 12g Damascus gun in multiple events and used 1 oz and 1 1/8 oz shells at 1200 FPS and less. No issues. This gun has 2 5/8" chambers.

I only have one gun with "short" chambers that were made for 2 9/16" shells and that's a 16g with pattern barrels.