doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com BIW Purdey

Ed, I will be happy to give you precise answers in about 2 hours, after lunch. I need to get my Rules of Proof copy from the garage.

mc, the more you post here the stranger and more bizarre you become...we can agree, that 12 gauge field guns are hard to sell at retail these days...and contrary to your claim that my 12 ga guns "go begging", please note that i have no 12 ga guns in inventory at the moment...

and speaking of begging...i beg you take your misery and mis information elsewhere and please do not burden us with it further...

hugh, sounds like answers may not be simple after all...

looking forward to results of your research...

Ed good, why spoil another interesting topic with your childish and ignorant behaviour? I really shouldn't waste any time over your antagonising and aggressive posts, but please let others read enjoyable and informative topics without your nastiness. Regards

mr martin, trying to increase ones knowledge is not childish...and it can be a cure for ignorance...

as you are from the uk, do you have answers to any of my five questions? if so, pls post them here, so all of us may become more knowledgeable...

and as for mc, i am trying to be patient with it, but it continues to plague us with negativity...

Edd you are a world class jerk you already have the answers for your questions like I said beating a dead horse the entire purpose of your questions is trying to slag the English box lock reputation because there are a lot of affordable plain perfectly serviceable guns on the market so it prevents you from hawking your beater guns on to unsuspecting buyer.suckit up

ah mc, suddenly, a ray of real truth perhaps?...we may be now gittin down to the motive behind your continued rude and abusive behavior towards me here...

could you be a commercial purveyor of english box lock guns, feeling threatened by my questions and concerns regarding the quality of the abundance of moderately
priced english made box lock guns now appearing on the u.s. market? if so, not to worry, as my modest hobby gun business is no threat to anyone...

I believe it will be worth reviewing what is Proof and what it is not. The governing legislation is "The Gun Barrel Proof Act of 1868". The goal of which was stated as protecting members of the General Public from the sale of guns that were inherently unsafe. In scope it covers both Domestic and Export Sales. It is updated periodically from time to time as conditions within the market change. In general terms it evaluates the ability of the submitted piece, Barrels, Action Body and Bolting system to withstand a single event overload/Per Barrel without damage or deformation.
I write this in the context of 1954 era proof, subsequent CIP edicts require metric markings and a double test per barrel. I've chosen 54 era for its simplicity and Imperial / inch units. As an aside the Rules of proof that apply to a gun are those in effect at the time of manufacture or most recent re-proof.
Of note here is it applies to the strength and integrity of the barrels ,action and bolting/(jointing). Nothing to do with forend iron tumblers,sears, safety, etc. Thus there is no such thing as a safety check other than barrel strength and so no "Safety Certificate " is ever issued, at least I've never seen or heard of one within the British gun trade.
For our working example Lets assume a Birmingham gun of 54 -89 manufacture.
A. barrels are viewed externally and internally for acceptable finish and lack of blemishes
B. A ground plug, approx 1&1/2" long of .729" is inserted to a depth of 9". It goes in!!
C. A ground plug, " " " .739" " " " " . It does NOT go in
This gun would be marked .729" NOTE it has not been measured at 729, it could conceivably be .738" but would be out of proof at .739" as proof is good for up to .010" above the Nominal dia marking.
A similar system of plugs measure chamber length in our example .800" and .810" . 2&1/2" to 2.550 depth would get a 12C (chamber) 2&1/2" length

Testing . Mean Service Pressure is 3 Tons PSI Lead crusher . Proof load would be 60-80% greater.vis 4.8-5.4 tons. The tester detonates by striking the firing pin or tumbler with a rod and hammer through a small hole in the rear of the test chamber.

Gun is the removed, inspected and marked.

So in answering Eds questions all we need to do is answer a basic binary question. IS THE GUN IN PROOF........YES/NO.?????

ED Goods Questions..
1. Do guns bound for export require Re Proof? NO guns offered for sale Need to be in Proof. Guns that are Out Of Proof require re-proofing.
1A.Shipped without Safety Certificate. As far as I know no such thing
2 Certainly don't cut antiques.? In proof NO/Out of Proof needs re proof prior to sale.
3. What constitutes an Antique in UK. I believe it depends on commercial availability of Ammunition. (Lagopus or Salopian could better qualify)
4.Do they use an arbitary date as US (12/31/)1898 ? NO see ans 3
5.Wall thickness part of Re-Proof? Wasn't part of original proof so No (other than if too thin may bulge or burst under re-proof)
6.What are the specs??? See Ans 5

I hope this helps, I, suffering fatigue and typers cramp
All the best,

hugh, thanks so much for your efforts...your review of proofing practices and your answers 1-6 are most helpful...

answers 3&4, suggests any gun in proof, with commercially available ammo, is never considered to be an antique, regardless of age?

and regarding Testing, it sounds like psi of test loads is a variable thing? what are psi ranges of test loads for various gauges?

concerned that english made guns, recently finding their way here, may not have barrel walls thick enough, to be safe for our higher pressure ammo...but then, i guess the same old, old ed 90-30 rule still applies?

but, certainly no high pressure loads in twist steel barreled guns...

SAAMI (voluntary) pressure standards are LESS than CIP "Superior Proof" standards, which carry the force of law, and we've had this conversation over and over ed.
But I'll play along in that someone may actually be interested in this.

Great Britain adopted the 1969 Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives standards March 1, 1980 but continued using Lead Crushers to measure pressure until 1989.
BAR however was not introduced until 1989, and the imperial proof marks could be requested from 1984 to 1989 using the Tons SERVICE pressure while the metric version used the Kg PROOF pressure.

2006 British Rules of Proof added this:
Part IV, “The Proof Load”, Number 27, Part A
Calls for a load of 30% over mean service pressure at a point 17mm or 25mm (about 1”), and at a point 162mm (6.38”) from the breech face a load of 30% over mean service pressure (at that point as determined by the Proof House).
The powder used in proof loads is not specified.

I do not know if Black Powder proof only can be requested but there are not separate Black Powder standards in the CIP regulations.

12g 50mm, 65mm, and 70mm “Standard Proof” lead or steel (limited to no larger than 3.25 mm and max. fps 1,300).
Numbers are transducer BAR converted to PSI.
Maximum Average (SERVICE) Pressure 740 BAR = 10,733 psi;
Maximum Statistical Individual Pressure 850 BAR = 12,328 psi
Mean PROOF Pressure 930 BAR = 13,489 psi

12g 76 mm = 3” LEAD “High performance/Superior Proof”
Maximum Average (Service) Pressure 1050 BAR = 15,229 psi
Maximum statistical individual pressure 1200 BAR = 17,405 psi
Magnum proof 1320 BAR = 19,145 psi

SAAMI 12g standards
Load pressure
Maximum average pressure for 2 3/4" and 3” shotgun shells will be 11,500 PSI +/- 900 psi, with some maximum extreme variability not to exceed an uber-max of 12,500 psi +/-900 psi
Proof loads:
If a manufacturer uses a SAAMI proof loads, then the gun will be proofed by a lot of no less than 10 shots of ammo loaded to a maximum proof pressure of 20,500 psi +/- 900 – 4600 psi, or uber max of 25,100 PSI; and, will be similarly a MINIMUM average proof pressure of 19,000 PSI +/- 900 – 4600 psi for an absolute minimum proof of 14,400 PSI.

12g STEEL regulations: the barrels should carry the High Performance Steel Fleur
de Lys stamp and be marked “Steel Shot”

Both 65 and 70 mm 16g standard is SERVICE 780 BAR or 11,313 psi;
MSIP 900 BAR or 13,053 psi;
PROOF 980 BAR or 14,214 psi.

Both 65 and 70 mm 20g standard is SERVICE 830 BAR or 12,038 psi;
MSIP 950 BAR or 13,779 psi;
PROOF 1040 BAR or 15,084 psi.


Vic Venters, Shooting Sportsman, March-April 2012, “CIP Proof”
“Although the Maximum Mean Pressures for service loads for standard proof (850 BAR) guns are 740 BAR, CIP regulated cartridge manufacturers typically work to lower pressures...between 450 (6,527 psi) and 650 bars (9,427 psi) as measured by CIP piezo transducers.”