doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Advice needed on Purdey

This. Why risk blowing up a fine old gun if you can just measure wall thickness instead. If they go .025 or more, you're good. Less, and it's wall-hanger. Easy.
JR

I regularly shoot guns well below 25 thou that are in proof - and safe with the loads for which they were designed and proved. Lots of fine guns had quite thin walls when new, especially pre WWII when light guns were popular.

Good grade steel (and Damascus) can be well below 25 thou towards the muzzle with no risk of burst, but they are easily dented.

So what thickness are you saying is your minimum, JohnfromUK?
JR

I believe Greener made one with walls near the muzzle .010 and it passed proof. Later he took a penknife and slit the tube to illustrate how thin it was. Point is from a safety standpoint it doesn't make a lot of difference what the minimum wall thickness is but it is very important to be satisfied the barrel has adequate strength in the first foot from the chamber. Now, if its too thin near the muzzle it will be more easily dented and repair can be a problem.

There is no specific figure as it depends on how good the material is (in the early days often how free from flaws it was), and where the measurement is taken. Walls can really be very thin near the muzzles and won't burst, but are very easily dented.
I agree that 25 thou and over is a fair "guide' to a near guarantee of safety but that is only one aspect, and 'proof' is a better test and will allow many that would fail the 25 thou test to remain in service.
Proof would also pick up hidden flaws and possible action weakness.

This is quite right.

I can tell you John that most auction houses will advise in their catalogues if the barrels are below .020

John

UK laws are not usually made respectively unless by an act of parliament they usually come in to force on the day that they are past or enforced.
So your gun with no proof at all so long as it was made before the date the law was put on the statute that is fine. This is the reason we have motor vehicles on the road that do not have seat belts flashing indicators or brake lights because they where manufactured before the relevant laws regarding those things where passed by parliament.
But there is always a but here in the UK when it comes to Tort laws just as an example Civil Tort could argue the point that because a gun has no proof marks the owner should (point of law to be argued) do all within his powers to see that the gun he sold was perfectly safe, so it could therefore be argued that the gun should pass through the proof house system to prove this fact. What I have just said may not ever happen at all but if you get a lawyer who will take your money and try to prove the case at your expense though it could go all the way to the House of Lords if you have the millions to spend.
As they say the Law is an Ass as well as being blind. And Lawyers really never loose financially no matter what the outcome of the case.

Thanks,
As it happens, I have not shot the gun (its a double 12 bore now converted to percussion) as I'm not a muzzle loader, but the relative I inherited it from did use it regularly (he shot grouse over a pointer with it). I have had it checked by a 'muzzle loading wise' gunsmith, who pronounced it in fine shooting condition, and it is on my certificate as a gun (rather than being treated as a wall piece). As a family piece, I don't think it will be sold in my time!
Thanks for the advice and it won't be me funding the 'test case'!

A lot of rhetoric on this thread to get to the short answer, "Measure the wall thickness.".