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