doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com W J Jeffery - Superior Proof?

My W J Jeffery is a 3' chambered gun proofed for 1 1/2 oz. of shot.



My apologies for the quality of the photo from my phone.

The serial number is 35560.

The Birmingham proof House website indicates that the Proof tests of 1925, 1954 and 1989 are equivalent to each other. The 3" proof test of the time was I believe 3 1/2 tons per square inch for a charge of 1 1/2 oz of shot.

From the earlier thread about out of proof British shotguns it appears that this might be translated into Superior Proof in transducer values.

Am I correct?

Can I use American Magnum cartridges in this gun?

Incidentally, although the gun is marked 3" and indeed does have 3' chambers it is only marked 12 over c in the diamond and not LC!

I would be grateful for any other info you experts can glean from the proof marks!

Thanks very much!

All the best

Skeeterbd

Skeeterbd;
I believe this 3� ton proof is about an equivalent of 10,640 PSI (This may not be exact but close) & as such is not the eqivalent of either modern day Superior proof or SAAMI specs for 3" guns.
There has always been some question in my mind on the LC mark. The proof rules for at least some of the years read the LC mark was to be applied to guns with chambers "Longer" than 3". However it seems that 3" chambers are found with both the standard C mark & the LC mark, so apparently some of the proofers were somewhat confused as well.

No, believe it or not you can't safely use the modern British 3" magnum cartridges through it either. The modern British 2 3/4" magnum round is o.k. though. Either that or load your own. I have two with similar proof marks and make my own 1 1/2 ounce 3" ammo for them or use factory 2 3/4" magnums with the 1 1/2 ounce of shot. Lagopus.....

It'd have to be a 4 ton/1200 bars/current Superior proof gun to use American 3" loads.

The old British 3" standard was considered to be equivalent to a 2&3/4" magnum . I do not know how this equates to modern loads but I think that the proof was 4 tons per square inch .

Thanks for the replies:

2-piper, Lagopus, L. Brown, Gunman:

From the Birmingham Proof House website and the 2012 Rottweil Shotshell Brochure and the discussion on out of proof Brit guns I am more or less sure that the 3 tons per square inch and the 740 bar (10735 psi approx.) service pressures are interchangeable as far as 65mm - 2 1/2 " (67.5 mm cases) are concerned.

But the 3 1/2 tons per square inch service pressure is a good 16.67 percent higher than the 3 tons per square inch service pressure for 2 1/2 inch chambered guns. Does this mean that 740 bar becomes 863 Bar (12520 psi) for the 3 inch 3 1/2 tons per square inch gun? Therefore, is the gun proofed to a higher pressure? Or does the lengthening of the chamber to 3 inch reduce pressure thus allowing barrels with less steel around the chamber area to allow for lower service pressures than 863 bar?

Lagopus:

If you think I can use 2 3/4 magnum CIP rounds in my gun then can I use the cartridges below in it?



However one flap has the folowing dire warning:



I readily admit that my Italian is less than perfect but I think that means that they are to be used in guns with "Superior Proof"! I know that shotshell length and shot charge weight does not prevent one of those things from going off like a minor nuclear bomb but I would have thought that CIP and "semi magnum" indicated that they are not supposed to.

If you learned gentlemen think I am confused then I am pretty sure you are right but I am not sure that I am sure!

All the best

Skeeterbd

P.S. I have further questions......

Skeeter, 740 bar transducer (the same as 650 bar crusher) works fine with same loads that can be used in a 3 ton gun. When the Brits transitioned to bars, there were only two levels of proof for 12 bore guns: 850 bars (crusher), which equals 960 bars transducer, which is now standard proof; or 1200 bars crusher, which equals 1370 bars transducer, and is now superior. Can't help you with the 3 1/2 tons, which is obviously higher than 3 tons, but which is not suitable for American 3" magnum loads (that would be 4 tons).

Doubt my Italian is any better than yours, but I also interpret it as indicating that those shells should only be used in magnum/superior proof guns. If yours is 3 1/2 tons, I wouldn't use them.

Very curious. One flap indicates they are o.k. and the other does not. Unless of course RC are only using standard and superior proof similar to what is happening in Britain. That would mean that they are not suitable for Standard Proof; which is obvious, and the only proof above that it Superior Proof. The warning is there to stop their use in Standard proof guns and after that there is no alternative between the two.

Maybe RC could clarify. I've not bought any 3" magnum stuff for a long time so have no recent boxes to see if it is the same with British ones. As Larry says, if in doubt don't use them until RC clarify. Lagopus.....

L. Brown, Lagopus

Thanks again for your replies.

I have to state the following although I am well aware that it validates nothing!

This gun was the first gun that my father handed over to me. However in the many years he used it before he gave it to me he fired literally tens of thousands (yes, tens of thousands) of American 3" 1 7/8 oz. magnum rounds through it in the blythe belief that 3" is 3"! In the twenty five years it has been with me I too have fired at least ten thousand magnum rounds through it without deleterious effect ( apparently) until I came upon this web site and read a few books and mayhap have learnt better! Perhaps this is a proof of sorts, but not to be relied upon!

I own a AyA 3" gun made as the "Super Solway" for Elderkin and Sons , a British Gunmaker, which I bought for �300 as a penurious student in 1983. It has 1200 kp/cm squared ( Kilo pascals per centimetre squared) which I was assured could handle any known 12bore cartridge (before the 3 1/2 inchers I believe) and has! However this gun has only about 2/3ds the thickness of steel around the chambers as my Jeffery. Possibly reflecting better later steel. Is this equivalent to Superior Proof?

Tomorrow is a public holiday here and I must spend time with my family! However the DEMON shall return

All the best

Skeeterbd