Hmm.. Better start looking for a similar device to check my 16 ga. Italian Lario Falc hammer shotgun... Mirror finish in the inside and for the age I doubt they would remain so shiny without being worked, thank you for all the info sir
Thank you, an excellent presentation explaining how "in proof" is determined. I was wondering however, about the minimum barrel thickness that you quoted as a minimum of 20thou. 20thou is very thin indeed, about the thickness of the plastic cartridge case! The thinest barrel that I can find is 60thou and most are considerably thicker than that. Am I misunderstanding something here?
Hi, 20 thou does sound very thin but it is regarded as the recommended minimum for an old English s/s. It’s measured at the thinnest part, usually a few inches back from the muzzle. More info in this article by Diggory Hadoke www.vintageguns.co.uk/articles/thin-barrels/
In the U.S., 12 bore commercial cartridges may develop up to 11,500 psi. Doesn't that exceed your proof pressures ("5 tonns")? Should U.S. buyers of British guns be concerned about that, esp. considering 100 year old metallurgy?
2,240lb x5 = 11,200 psi pretty close and if it was proofed at a certain pressure I wouldn't be concerned about the metallurgy of the steel unless it showed signs of fatigue
Another fascinating video,thank you! Kindest regards.
Even online, I’ve struggled to find a good list and pictorial explanation of proof marks
Never to old to learn something new. Thanks
Excellent presentation, very informative.
Hmm.. Better start looking for a similar device to check my 16 ga. Italian Lario Falc hammer shotgun... Mirror finish in the inside and for the age I doubt they would remain so shiny without being worked, thank you for all the info sir
Thank you, an excellent presentation explaining how "in proof" is determined.
I was wondering however, about the minimum barrel thickness that you quoted as a minimum of 20thou. 20thou is very thin indeed, about the thickness of the plastic cartridge case! The thinest barrel that I can find is 60thou and most are considerably thicker than that.
Am I misunderstanding something here?
Hi, 20 thou does sound very thin but it is regarded as the recommended minimum for an old English s/s. It’s measured at the thinnest part, usually a few inches back from the muzzle. More info in this article by Diggory Hadoke www.vintageguns.co.uk/articles/thin-barrels/
20 thou is 20 thousandths of an inch. or 0.020 inch.
20 thou is 0.508mm
Thank you for the link Doug, a very interesting website!
That was interesting. Are there different standards for guns that use black powder cartridges?
In the U.S., 12 bore commercial cartridges may develop up to 11,500 psi. Doesn't that exceed your proof pressures ("5 tonns")? Should U.S. buyers of British guns be concerned about that, esp. considering 100 year old metallurgy?
2,240lb x5 = 11,200 psi pretty close and if it was proofed at a certain pressure I wouldn't be concerned about the metallurgy of the steel unless it showed signs of fatigue
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