As many of you will know, I reproof most of my stock guns before sale, 'whether they need it or not'! Actually, not quite true as the tightening of the proof tests in recent years has made it a rather risky business with rivelled and bulged barrels left, right and centre.
And that is the point: I have become accustomed to barrel failures but this week I got a Blanch back from the proof house with a significantly higher level of failure!
The picture below shows the action bar has totally failed in the thin region below the hinge pin and in all honesty, not even the miracle workers I know can fix this one!
Some in non-proof countries will say that this only goes to show how terrible and destructive the proof test is.
For myself, yes, I am well out of pocket on this gun but then that is why I reproof most of my stock guns: I really don't want to be responsible for any unseen flaw in barrels and action even if the gun could have been sold without reproof.
So I will continue to reproof most of my stock guns and hope that this sort of almost total loss doesn't happen again too soon.
Oh, and by the way, if anybody want an elegant 1880's paperweight for their desk I would be happy to sell it to them...!

How much for the paperweight Mr Barclay?...Geo

Wow - sorry that happened.

What kind of condition was the gun in when it was submitted?

Was the everything original - hinge pin, bolt, etc?

Did you tighten everything up before submitting?

What could cause that kind of damage -- action flexing, hinge pin being pushed forward by bbls?

OWD

Serious question, why not, if it's in proof, run a quick couple boxes of proper shells through it off of a rest. Then, have and experienced gunsmith inspect it? I think it's an odd mindset to feel better about significantly overloading the intended design of a gun.

The failures that you mentioned seem to me like the gun stayed together. Wouldn't a shooter just stop shooting if breaks? Is there any assurance that a gun won't fail if it has a stamp on it? There was a fellow here that shared a barrel failure during the first round or two of clay targets after a fresh reproof.

I don't know how it is out by you, but there're 'experts' here that'll recommend shooting longer shells than are stamped on a gun. If, the shooter is 'responsible'. It's a complete disregard for the concept of proof, but considered normal for classic gun insiders.

Toby, thank you for your thoughts. I hope you don't take my comments as some type internet trolling against you. Maybe, some form of nondestructive testing can be devised, along with buyer education, would save unnecessarily losing these guns forever.

Did you knowingly send that gun to the proof house off face? My bet would say that you thought it would pass proof. It seems to me like the proof house can put any reason down for failure, other than massive over pressure. Only the best to you and yours.

Thanks for posting that pic and description, Toby.

Regarding proof testing, there will always be that question in my mind ................. Yes, if failed proof because the frame broke. But, would it have ever broken there using normal and appropriate loads? Though I cannot, obviously, prove it ....... I'll bet not.

You're to be commended for going the extra mile in trying to screen your guns that you sell to users. I have no bone to pick with you at all. You are doing what you believe to be a "best practice".

Sorry for your monetary loss, however.

All my best, SRH

It broke because it was flexed beyond it's elastic limit.

This is obvious, of course, like stating a ship sank because it could no longer float.

Frames are case hardened to provide a durable surface, while allowing a certain amount of flex.

The 'proof test' in this case proved where the frame was brittle.

The root cause of the failure is as simple as that. The question is was this caused by fatigue and did it present a danger going forward.

My personal opinion is no, and no.

A microscopic analysis of the failure and adjacent areas may conclude otherwise.

Until somebody does that, we're just guessing.

I agree with most comments above, we will never know if the gun would have lasted until the end of time or let go on the next round. And anyway, that type of failure is not particularly dangerous, as Craigd says above, the shooter just needs to stop shooting.
The reason I reproof is partly because I can but mainly because I get asked unbelievably uninformed questions at every show I exhibit at, demonstrating the level of ignorance amongst the gun buying public.
Also a lot of people in the USA reload which is an excellent way of producing mild cartridges for vintage guns. It is also an excellent way of producing proof charges if you don't know what you are doing or are distracted by the dog peeing on your foot!
I have no way of knowing who is going to land up shooting my wares, their level of knowledge, stupidity or if their dog is house-trained.
I also can not be sure that someone isn't going to block their barrels with a 20g shell or a wad of snow and turn their carefully selected recipe into a proof load.
As Stan says above, its about going the extra mile.

There's a failure tag in the picture with a clear reason, no guessing. It is the law there and recognized not only by that nation, but all other CIP member nations. Even though we're willing to question that recent arbitrary proof changes are wrecking guns that likely would've passed under previous standards, I still think it's a slap in the face of a classic gun expert who couldn't anticipate an elastic limit failure point, but knew if it were on face or not.

edit to add, thanks much Toby for your follow up comments. I don't question your decisions for a moment, only wondering out loud if this process assures us of anything.

Even if it was B.P. originally, that's not where you'd expect something to crack. I know hindsight is a great thing but those square corners the crack started at seems like an obvious place when you see it now, but it's worrying if you have an old gun you'd like to have re-proofed.
I'm guessing it was off face after their proof loads and not before

Of course Nick.

Had it been off face as submitted they would not have fired the proof load. This is called a 'view' and is the initial part of proof procedure.

The 'official' reason for failure to pass proof is 'off face' (no kidding).

This is an inevitable consequence of that big friggin' crack.

Mr. Barclay does make some valid points.

That gun wasn't designed or intended to see the level of proof that the Birmingham proofhouse uses today. As the photo clearly demonstrates.

I understand the notion of trying to see the gun is ready for another lifetime of use. That said, I can't fathom why anyone would expect a gun of this age to pass current proof levels, repairman, or, buyer.

A shame.


Best,
Ted

Horrow show...what a shame for such a lovely frame to end it's life that way.

I'll agree with Ted here. What would we prove by loading a 19th century percussion gun with a hefty charge of Bullseye? And, even if it did survive, how can we be sure it hasn't exceeded the elastic limits of its' barrel or action so that the next normal load doesn't finish it off? I think a gun that was seriously off face would be much more likely to have a case failure than a breakages of the frame. I'd want to throat-punch the MF'er who signed that failure tag.

We have some old wooden covered bridges in my area that are still in use. We don't test them by driving heavily loaded tractor-trailers over them to prove them. We instead post and enforce sensible weight limits for them so we can continue to enjoy them.

For all those who think the gun was 'off face' when submitted for proof, please read Shotgunjones' post on page one. I thought you would all know how the proof test worked by now.
What was I saying about ill-informed opinion...?

George it would've made a pretty table lamp...

Makes one wonder...

Fascinating failure! Not where it is expected, the junction of the breech face to the flats but at the underside of the cross pin. Knowing the preppng for proof this gun presumably was "fitted on the circle" yet it still took a fair amount of stress on the cross pin.

Makes me wonder about the Poisson effect in thick walled cylinders which show a contraction when stressed radially and inevitably a recovery when the pressure is reduced, both phases occurring rapidly and violently. I wonder if it contributed to this failure.

Exactly your point I was alluding to Toby.

I'm not sure of the Proof House nomenclature. "Action off Face" ? Is that what they call a cracked bar ?

What exactly is "ill informed" about the realization by several of us, that it may not be wise to stress things like old guns or old wooden bridges well above their intended design limits? It seems to be common knowledge that the Birmingham Proof House is testing to some higher standard, which is apparently causing guns to fail that likely would have came though unscathed in the past. If you loan me one of your shotguns and I fire a super-hot and inappropriate handload that sends the barrels flying several yards down-range, would you be upset if I returned the shattered pieces to you and said, "This thing's off face!"

Only one person questioned whether the gun was off-face when submitted for proof, but he quickly said he'd bet you thought it would pass proof, i.e., he assumed you did your own educated and informed visual examination prior to the Proof House doing the same. Sorry about your luck, but when you posted this for discussion, you might have guessed that not everyone would agree with your decision to let someone destroy your gun.

Looks like 70 mm chamber by the proof house note.....that was probably the 1st mistake, reaming/lengthening the chambers on a gun that old. Then, 2 3/4" proof loads.....Yikes! No wonder the old girl failed.

I think the new proof procedures are ruining too many guns which should have passed proof. I understand it's the way it is and the law is the law but to change the rules this much just puts a lot of guns at unnecessary risk. I guess I'm like a lot of people and wish they had two standards so period hubs could be proofed today like they were designed to be proofed at when made. But they don't so it's roll the dice and see what happens. Kind of makes you sick when a gun fails that you'd expect to pass but I'm sure it's always been like that.

Don't forget, we are interested in saving/using the fine old guns; but there, the ones that make the rules have been doing everything they can to do away with guns, for years.
Mike

It seems to me that the whole purpose of government sponsored proof is to insure that the gun will be safe for the least informed shooter who may use it. If layered proof standards were adopted to prevent the destruction of older less strongly built guns all the public would know was that it passed proof. They would shoot whatever shells they had available, when what they should be shooting was low pressure...Geo

The choice, then, would seem to be between having fewer dumb shooters or fewer fine guns? I know which one I am going to pick...

What is the source that indicates more older guns are failing proof. I'm interested in learning what the Birmingham Proof House has to say about revised procedures and failure rates.

If? I thought the proof markings were 'layered' now. There are so many questions here about folks asking what proof marks mean. Are the marks really so clear. If a gun is marked 12 ga., now the general public is protected from harm by using anything that comes out of a box marked 12 ga.?

I think the topic started off by the original fellow noticing that some procedure at the Birmingham proof house has changed recently which translates to more proof failures. Was the change arbitrary for a preferential purpose, or was there evidence of public harm from inadequate proof testing?

The only layers of proof I'm aware of are black powder and smokeless. Well, I guess there is a 'new' steel shot proof. The chamber length is on the gun or is readily measured...Geo

There are a few misconceptions here concerning proof/reproof. Mr. Barclay didn't mention whether the gun had been reproofed previously at some time. However, although it's much more likely the gun started life as a 2 1/2" gun, we don't know that for sure. But since the proofhouse tag says 12/70, then that's either what it was to start with, or else--somewhere along the line--it had already passed one reproof with the lengthened chambers. Otherwise, it would not have been a case of whether Toby WANTED to have it reproofed just to be on the safe side. If the chambers were lengthened from 2 1/2" to 2 3/4" and the gun had not been reproofed, then it would be illegal for him to sell it without submitting it for reproof.

You won't find chamber length marked on 1880's guns unless the gun has been reproofed. Chamber length wasn't a required proofmark until 1925.

As for the pressure of a current reproof, it is my understanding that even a 2 3/4" gun, if the owner so requests, can be proofed at the "standard" level (rather than the much higher superior proof level). Per the Birmingham Proofhouse, that is something a bit less than 14,000 psi as we'd measure it in this country. British/CIP standard proof guns use shotshells that generate pressures of slightly less than 11,000 psi. So while a standard proof load is indeed an overload, there isn't nearly as much of an overload as there is between the standard service pressures of American shotshells and the pressures of American proof loads. 12ga SAAMI service pressure is 11,500 psi, against a proof pressure of something in the 18-19,000 range.

Current British proofmarks are pretty clear. If the gun is standard proof, it's marked STD--and you use the shells suitable for a standard proof gun. If it's superior, the marking is SUP--and hotter American shotshells will work just fine. Older British proofmarks can be somewhat confusing unless you know how to decipher them.

Buzz, the pressures for 2 1/2" proof are exactly the same as for 2 3/4" proof. The only difference between the two proofs is the length of the chamber. If I had a barrel failure in the critical area where the chamber has been lengthened, I would of course blame the lengthened chambers but that has never happened to me. Failures have to date all been rivelling of the central part of the tube (often in areas of less than ideal MWT) or bulges at the choke forcing cones (usually with choke constriction of over 0.020"). Once or twice a weak action has come off face but this has usually been a thin, early breech loader such as a converted pinfire. A couple of times the lumps have come loose and had had to be re-brazed.
L.Brown, This gun was heavily pitted but with very good MWT's and substantial metal in the chamber area. To remove the pitting, the barrels had to be lapped to beyond their proof size so it HAD to be re-proofed. Given the nature of the 2 1/2" and 2 3/4" proof tests (see above), it was a no-brainer to lengthen the chambers. So when the gun was submitted for proof, it had 70mm chambers, the gun would have been measured at 'view' and when the gun failed (or passed) the paperwork would record it as a 12/70. It would not have to have ever passed 70mm proof to be ticketed as such.
Actually, all proof is done at the 'Standard' level for the chamber length UNLESS you request 'Superior'.
Craigd, The reason why proof is valued by most shooters in the CIP area is that we CAN go into a gun shop and if the box of cartridges says it is suitable for the chamber length of our gun, we can use it with impunity. Obviously, once the gun leaves the CIP area, eg goes to the USA, there is no such standard and ignorance of what a suitable load might be could get someone into trouble. I make no criticism of the situation in the USA, I just try to manage the risk as best I can.

I guess having a gun marked with a reproof has no bearing on what happened to the gun after reproof. Of course a 2017 reproof certainly should be a more reliable indication of the gun's condition than a decades old reproof, but I suppose no guarantee.

So what it boils down to is that if Billy-Bob screws up while reloading because the dog pissed on his boot and distracted him, or because he drops an inappropriate magnum load into the chambers and blows the damn thing up... then he is ill informed and irresponsible.

But if some official at the Birmingham Proof House drops an equally inappropriate 18,000 psi or greater proof load into an 1880's gun that likely was originally chambered for early 2 1/2" loads, then that is informed and intelligent.



Given the facts and present day realities, I wonder why on Earth you'd expect a different result if you keep permitting the Birmingham Proof House to touch off totally inappropriate loads in vintage doubles??? I recently bought a .450 BPE double rifle. If I attempt to turn it into a .458 Lott and blow it up, that is not the fault of the guy who sold it to me, or of the Leige Proof House.

EDIT: If the standard proof pressures have not changed, then how do you explain the recent news that a greater than usual number of guns are failing proof? It would appear that something had to change given the greater frequency of reports of failures. I add this edit due to the new previously undisclosed information that this gun HAD to be re-proved due to barrel honing and chamber lengthening taking it out of proof.

I am sorry for your loss. I take it that proof failures are still very uncommon. What % of guns submitted fail I wonder. The fact that the barrels passed, but the frame failed, does seem to suggest that even after honing the gun was well worth the reproof attempt. After all I suspect far more barrels fail than any other cause of reproof failure.

It's not true all of us over here in the US are prone to shooting super hot, high pressure loads in our guns. We can buy lots pressure loads or reload our own. A good many here can either read or hunt with someone who reads for them and all of our factory shells, in this country, strongly state not for dmascus use. So we should be buying correct, over priced, fancy pants, ammo from exotic countries like GB.

We don't mind our dogs pissing on our foot unless the wife is not home. It's her job to let him out when nature calls so she has to clean it up. If she's gone we have to figure out which kid had the duty, which can get tedious. Besides that's why men wear boots to keep their feet dry unlike ladies who go around bare foot, even outside the kitchen.

What I really like about guns out of proof is I can use that fact as a damned good bargaining chip when buying. DANGEROUS!

There is a huge difference in having to re-proof in order to be able to sell a gun and just having it proofed to go through the process for "peace of mind". Stupid can not be fixed. Gov't regs must be followed to do business. While our SAMMI standards are higher than CIP it isn't that much and those are maximum pressures and not all loads are to that level. The problem is there is no way to know without pressure testing each lot of commercially loaded shells , and reloading component lots to really know. We can do the best we can to make educated guesses, and use high quality products. Proof houses are to provide gov't oversight of new manufactured firearms. The laws are not designed to have anything to do with fine collectable firearms. It all comes down to money. Fine vintage firearms are a tiny niche in the overall industry. "They" are from the gov't and are here to help !

I like The Onion too.


___________________________
Smells like stale macho.

Thank you for the follow up comments. I think this is a good thing, now the shooter is engaged in what they're doing. Still, if in proof for 'standard', that alone doesn't prevent the chambering and firing of a 'superior' load.

In your opening comment, you mention that in recent years you have become accustomed to more barrel failures, though this example is different. Do you have any thought as to how much more pressure is involved with 'standard' proof? My understanding is measurement procedures have changed, so the proof loads are now different? If the guns are failing more often than in the past, is there some thought that the guns that pass have a better safety margin? Do you have any concern for the possibility that a future change happens that results in a higher failure rate than currently. Sorry for all the questions, I just find it truly interesting.

Looking at the tag, I suspect the mark "action off face" is a bit of understated British humor, applied after proof load number 1 undid a lot of good gunsmithing.

Of course the gun passed view before being submitted, but, proof has changed in England. Each barrel gets fired with two proof loads, one that generates maximum proof in the chamber area, and another that generates it at a point about 9" from the breech. THIS is the cause of so much scrap iron we are witnessing here, from this point in history.
If it were my gun, and I lived in Merry England, I would have specified black powder reproof, if that option is still available, and happily shot it with light loads the rest of my life. It wasn't my gun, and I don't live in England, so, perhaps now it will provide parts to get a similar gun working someday.
Keith, I love your analysis on who blows up guns, and how could anyone believe one was smarter than the other. Hilarious.
Still makes me quezy, looking at that action bar.
Toby, unless I am mistaken, the owner could have used the gun the rest of his life, even if it wasn't in proof, but, it couldn't legally be sold.
It might be time for you guys doing the repairs over in England to do some soul searching, and come up with the equivalent of a black powder reproof with the proof house, for guns that are still useful, but, not suitable for more modern ammunition. Black powder reproof was once available, it may still be.

Better that than creating what we see here.


Best,
Ted

Just a question, but is the more destructive proof currently in vogue a result of European Union CIP proof requirements? Will Brexit have any bearing on that question?...Geo

Thanks Ted, there's the problem. Maybe a third proof load that generates maximum pressure 18" from the breech would help a little. So much for the ole graphs showing maximum pressure builds just pass the chamber.

It is interesting that the most common increases in proof failure that were noted in the beginning, had to do with barrel failures that are generally blamed on obstructions when these discussion come up.

The pressure curve charts which I have seen all show the point of max pressure coming within the chamber itself, not beyond it. The curves will then cross inside of 4 inches with the higher ones becoming the lower ones & the lower ones becoming the higher ones.
I am forever grateful that we do not have those proof laws to contend with in the US.

I have a difficult time believing that any barrel, old or modern, could withstand proof pressure 9" from the breech.

I gotta call BS on that one.

It would be a pointless test anyway.

Perhaps they have jacked up the loads so as to carry more pressure down barrel, but max pressure at 9"? The pressure there should be 3,000 psi or so, why in hell test it at 6 times that?

How would you even build such a cartridge? With TNT and a 1 millisecond delay fuse?

Toby--Thanks for the clarification. I think many of us have seen guns that are out of proof due to bore diameter, but with good MWT are very likely perfectly safe with appropriate loads. As this one might well have been, had you not been required to submit it for reproof.
Craig--As pointed out above, although you can't cure stupid, you can deal with ignorance via education. And this BB is a good place to get educated about vintage guns. Even some vintage American guns with factory 2 3/4" chambers aren't necessarily safe with every American factory load. Without a careful inspection, preferably by a gunsmith who knows his way around vintage guns, the average shooter has no real way of knowing what kind of life that gun has led since it left the factory. But unfortunately, a whole lot of Americans will take that 2 3/4" mark as a guarantee that it will work just fine with the heaviest and hottest off the shelf loads.

Ted, not one hundred percent sure but I think You can only request black powder proof if the gun had only ever been proofed for black; once submitted for nitro at some time in its history then it has to pass a nitro reproof.

I think Toby is taking the sensible option. His reputation would have taken a knock if he had sold the gun and it had failed after a few rounds with its new owner. Better to fail in a controlled environment.

I sold a good strong steel barrel hammer gun a few years back. It was 1 thou. out in one barrel so off to the Proof House it went having the chambers lengthened from 2 1/2" to 2 3/4". It passed no problem as I was sure it would. I sold it on and the barrel bulged and split just forward of the forend during use. The gun was returned to the Proof House for inspection and they concluded it was due to a barrel obstruction. Having it re-proofed prior to sale indicated that I had at least not sold a gun in a dangerous condition.

I have only ever had one gun fail and that was a 20 bore that cracked at the action at the angle between the standing breech and the flats. It was repaired by stainless steel welding in the gun trade and re-submitted and this time passed. It is almost impossible to see the repair other than with a magnifying glass. I have sold it and given the buyer all the details but having passed re-proof both he and I are confident that it is good for use. Lagopus.....

That's a good story Lagopus. I can see some very good aspects for proof but I also can see the downer side of it too, like the ruination of Toby's Blanch. Subjecting a 140 year old gun to violent proof does not make a whole lot of sense to me!

Call BS on this:

wwwgunproof.com/PROOF_Memoranda/RULESOFP.PDF

Pay attention to part IV, "The Proof Load" number 27, part A, that calls for a load of 30% over mean service pressure at a point 17mm or 25mm, and at a point 162mm from the breech face a load of 30% over mean service pressure.

Two loads, two different places where peak pressure is generated. I don't believe 162mm is exactly 9", but, that might be splitting hairs at that point.


Best,
Ted

Ted , I think you are misinterpreting what it's saying.The interpretation provided to me was that the Proof Load must generate at least 30% more than Service pressure at both the 17-25 mm (Peak or max chamber pressure) and maintain that 30% overage to a point of 162mm (6&3/8th Inch). Maximum 2& 3/4" load
service pressure at this 6.4" point was 1.8 tons PSI lead crusher,4030 psi lead giving a proof cartridge requirement of 5250 psi lead at 6.4" they do not in fact have two different loads. one load fired twice that meets both chamber and 6" requirement
Hope this helps clarify.

OK, thanks for the reference Ted.

The link won't work, but it's simple to find with a search.

I believe you misinterpret that section.

In building their proof loads, The Masters are directed to apply at least 30% overload both in the chamber and at 162mm.

This does not necessarily require two cartridges.

Here's the key point. When measuring 'service' pressure at 162mm, the value will be someplace between 2.000 and 4,000 psi depending on which chart you run across and from which era. The intent of the proof rule is to apply 30% more of THAT measured pressure, not 30% more than PEAK pressure at that point.

They are not testing the 162mm point with chamber pressure.

It is possible that to achieve this, two cartridges are used. The reason for it would be to reduce peak chamber pressure while still applying sufficient PSI at the 162mm point.

I did find one black powder proof curve that showed near 2 tons of pressure at approximately the 9" point, so this appears to be nothing new.

LONG VERSION

2006 British Rules of Proof
http://www.gunproof.com/Proof_Memoranda/RULESOFP.PDF

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.

Calculation of Proof Pressures.
26. — Where not specified in C.I.P. Tables of Pressure, Proof Pressures shall be based on the mean maximum pressures developed by firing not less than five Service Loads or Special Loads.

Relation of Proof Pressure to Service Pressure
27. — Where not specified in Tables each Proof Pressure shall be calculated so that it exceeds the highest mean Service Pressure or (in the case of Special Definitive Proof) the mean pressure developed by the Special Load of the arm by an amount which is equal to or greater than the amounts specified below:
(a) In the case of Provisional Proof of an arm, or barrel intended for an arm, of the First Class, when pressures are measured at a position 17mm or 25mm from the breech face, the amount of 30 per cent; and at a position 162mm from the breech face, the amount of 30 per cent.
(b) In the case of Provisional Proof of any other barrel or arm, when pressures are measured at a position indicated in C.I.P. Tables or where not so indicated as the Two Companies may think suitable, such amount as the Two Companies may agree.
(c) In the case of Definitive Proof or Special Definitive Proof of an arm of the First Class, when pressures are measured at both 17mm or 25mm and 162mm from its breech face, the amount of 30 per cent at the first point, or such increased amount as the Two Companies may agree.
(d) In the case of Definitive Proof or Special Definitive Proof of an arm of the Second or Third Class measured at such a position as the Two Companies may consider suitable, the amount of 30 per cent.
(e) In the case Definitive Proof or Special Definitive Proof of an arm of the Fourth Class measured in such manner as the Two Companies may consider suitable, the amount of 30 per cent.

28. — (1) The minimum Proof Pressure for an arm of the First, Second and Third Class shall be that set out in C.I.P. Tables of Pressure or where not so set out, be such as the Two Companies shall from time to time determine.

Great Britain adopted the 1969 Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives standards March 1, 1980.

The Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives standards were not ratified until 1969.
http://www.cip-bobp.org/homologation/en/tdcc_public?page=1&cartridge_type_id=7

12g 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)
.....SERVICE pressure 740 BAR = 10,733 psi; Maximum statistical individual pressure 850 BAR = 12,328 psi
.....PROOF 930 BAR = 13,489 psi

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

12g STEEL regulations: the barrels should carry the High Performance Steel Fleur
de Lys stamp and be marked “Steel Shot”
http://www.chircuprodimpex.ro/produse/al...-ammunition.pdf

Both 65 and 70 mm 16g standard is SERVICE 780 BAR or 11,313 psi;
Maximum SERVICE 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;
Maximum SERVICE 950 BAR or 13,779 psi; PROOF 1040 BAR or 15,084 psi.

Maximum 2& 3/4" load service pressure at this 6.4" point was 1.8 tons PSI lead crusher,4030 psi lead giving a proof cartridge requirement of 5250 psi lead at 6.4"

I'm really confused. CIP standards are clearly measured by piezoelectric transducer pressures, not lead crushers. 1.8 tons converted to piezo psi by Burrard's formula is 4928 psi.

Without knowing the pressure curve of the powder used by the Proof House, I don't believe we can KNOW the target pressures at 6.38"

Yes we do. It's 'at least' 130% of mean service pressure.

I think this all suffers in translation from the English.

Blackpowder Pressures from Sporting Guns and Gunpowders: Comprising a Selection from Reports of Experiments, and Other Articles Published in the "Field" Newspaper, Relative to Firearms and Explosives, Volumes 1-2, 1897



Definitive proof was 6 1/2 Drams Proof House Powder with 1 2/3 oz. No. 6 shot = 4 1/2 Long Tons LUP or about 14,000 psi.
6" Proof Pressure was not reported but looks to be about equal to 72 gr. C&H No. 2 T.S. (somewhat similar to FFFg) = 3.2 Tons = 9,632 psi

So what is the Mean Service Pressure suppose to be at 6 3/8"? CIP doesn't list a target number.

That's the chart I was referencing, Drew.

I eyeballed the 9" point which is where this all started and guesstimated 2 tons.

That's a whopper of a proof load, and if the pressure curve is anywhere near correct the strength of blackpowder proved guns has been underestimated for generations.

Perhaps this is the chart that gave rise to the idea that black maintains higher pressures down barrel longer than smokeless.

"So what is the Mean Service Pressure suppose to be at 6 3/8"? CIP doesn't list a target number."

'The Masters' are apparently able and authorized to measure that in their pressure guns from representative cartridges and then load their proof rounds accordingly.

It's not important that we know, only that they know.

Hey! Maybe that's the root of the proof failure epidemic.

Suppose CIP cartridges have gotten hotter and proof loads have followed?

I know that sounds blazingly stupid since the cartridges are supposedly tested, but do they test at 162mm? If so, why no data as Drew points out?

A not so bad guess would be that CIP cartridges are probably lower pressure than their rating to try to keep the liability hounds at heel. And, the standard greeting is, Hi, I'm from the proof house and I'm here to help.

Very interesting. We've discussed the 1929 Hunter Arms Proof Load Pressure Curve Chart in the past
http://library.centerofthewest.org/cdm/singleitem/collection/WRAC/id/8149/rec/107

12g 2 3/4” was proved with 6.5 Drams FFFg with 1.687 oz. shot = 14,200 psi at 1"
Pressure was about 9,500 psi at 6"
Pressures were measured by crushers (LUP - Lead Units Pressure) and modern piezoelectric transducer measurements would by 10 – 14% higher

Well, CIP maximum is generally lower than SAAMI maximum so to get any decent performance CIP shells appear to need to be loaded closer to maximum peak under their standard.

The total work done by a shotshell is represented by the area under the pressure curve, so a lower peak pressure MUST be offset by some additional pressure down barrel someplace.

Charts 'proving' that this is 'not much' have been posted, but the fact remains that to get to 1200 fps for example, any shell loaded under any standard has to do the same work.

Being European modern re-proof means I'm willing to pay extra for ole' grand daddy gun so tested. Able to shoot modern ammo of appropriate pressure is big plus. In America people collect guns and sometimes shoot them knowing that "Model T can't be driven at 80mph w/o engine blowing long before that speed is attained". Americans have RST and Polywad catering to people shooting antiques w/o modern re-proof. When recommending light weight game gun on European forums the likely candidates are vertical guns from Beretta, B.C. Miroku and if looks are acceptable Merkel Bros. it is almost never something real old with short chambers or twist or damascus barrels. The gold standard for SxS classic is Webley & Scott 700 series from Birmingham sadly discontinued many years ago. There are suitable copies from Germany, Italy, Austria, France, Spain,..... Limited new SxS game guns means Fabrique en Turkye. Different worlds different beliefs and customs.

Toby, a question for you.....: I'm assuming the barrels on your Blanch survived the proof testing with only the action failing. If you fit these barrels to another action will they then have to go through proof AGAIN to be legal? Also, I'm sorry for the loss of the action. Having a love for antiques as I do, it almost makes me teary eyed to look at the Blanch action photo.

Interesting discussion. We probably need to start with the obvious, which is that there is only ONE peak pressure, and that occurs in the chamber. Pressure doesn't start high, drop, and then go back up. It drops all the way from the chamber to the muzzle. The only difference is in how quickly it drops. Different pressure curves . . . but they're all headed in the same direction.

And it's quite possible to obtain "decent performance" from shells that are loaded well below max service pressure. We don't care what the pressure is at the muzzle. We only care about sufficient velocity to give us sufficient energy (and penetration) to do whatever we want the load to do. For several years, I've used a reload for pheasants in a Federal hull with Fed wad and primer, 22 grains Unique, 7,200 psi. That's well below both SAAMI and CIP max service pressure. Yet it yields 1200 fps velocity at the muzzle . . . and the pheasants don't like it at all. That load may well retain a higher pressure as it moves down the barrel, relative to peak pressure, than does a load that generates 11,000 psi peak pressure. But performance, based on my field tests, is definitely "decent".

That peak pressure is maintained for only a very short distance within the chamber. Obviously for a 7,200 psi & a 11,000 psi to end u giving the same velocity to the same weight charge that difference has to be made up. Generally speaking this "Makeup" space will occupy the entire rest of the barrel, which may contain on the order of 100 times the length of that occupied by the peak. Thus it doesn't take a large increase in the pressure ""Down the Barrel" to compensate for a major difference in the peak.
One of the main concerns here is to be sure the chosen powder is compatible with the reduced pressures to insure it will burn consistently & reliably in ant temperature the load is apt to be used in, otherwise squibs & failures can occur.
Unique should burn well down to that 7200 psi figure which your results would tend to bear out. but personally I would likely not trust it much lower than that. As I recall the Federal primer is a comparatively Hot primer. This is good when working to minimum pressures. Even though "Mild" primers can lower pressures even more they can also be a major factor in incomplete ignition & combustion at the lower pressures.

So Larry... your pet load seems to be loaded closer to CIP maximum than SAAMI maximum. That was my point in the context of the discussion, not that it's terribly relevant.

Neither CIP nor SAAMI member companies 'load below their rating' for liability reasons. That's one of the purposes of the standards in the first place. They are quite free to load right up to maximum peak pressures, and certainly sometimes do.

We were trying to figure out what the pressure might be at the apparently arbitrary 162mm point which is about 6 3/8" from the breech face and not the 9" quoted in this and other discussions as the mythical 'peak pressure point of a second proof load'.

The intent is clearly to test not only the chamber but the forcing cone to a reasonable distance.

Another interesting thing to consider that was mentioned earlier in this discussion is that since this was not a catastrophic failure, the shooter could just have stopped shooting and all would be well.

He could have, IF he had noticed the problem and heeded the warning of impending major failure.

Well, who would be that unobservant you ask...

I know of three instances where a shooter had ample warning that something wasn't right, yet persisted and had a catastrophic failure.

In fact, I'm of the opinion that a sudden unexpected failure is rare , and that the gun will usually give warning of it's distress before the catastrophic event.

It's up to the shooter to be in tune enough to recognize it, and STOP to take stock of the situation should anything unusual occur.

The only exception might be in combat.

Jones, I think most of us understand that the major ammo manufacturers work for consistent velocity and, as you point out, only worry about staying below the max average service pressure. But I think the Brits may, on average, provide more of a cushion below the allowable service pressure than we do. And I think that's because they have a whole lot more old guns (as a percentage) still in service--including, of course, Damascus--than we do. That probably has something to do with the fact that our guns were designed for rugged use, more on the order of tools, and that they were more likely to be the victims of neglect (not seeing a gunsmith until something broke) than British guns. Vic Venters, in one of his "Gun Craft" columns for Shooting Sportsman (my copy unfortunately "ate" the date of the issue in question!) wrote:

"Although the maximum mean pressures for service loads for standard proof guns are 740 bars, CIP-regulated cartridge manufacturers typically work to far lower pressures--usually between 450 and 650 bars as measured by CIP piezo transducers."

Re my 7200 psi pheasant load: I'm not one who believes in ultra-low pressures for vintage guns. As pointed out above, they can sometimes suffer from inferior performance in cold weather. (I can remember old reloading manuals carrying notations that such and such a load was not a good choice for cold weather.) I've field tested that one down to at least the teens above 0 and it works quite well. Any more, much colder than that and I may very well stay home!

While we don't seem to know what pressure test point is being targeted at 162mm's from the breech, there does seem to be some agreement on what a shotgun shell pressure curve looks like. It might be that 'testing' downstream of the forcing cone is intended to exceed stated proof pressure at 17 and 25mm's.

Say, for discussion, that the second proof load firing is the 162mm test. I wonder what percentage of failures are racked up on that second shot. Rivelling, bulges and a cracked frame? Maybe, there's a possible reason why, 'tightening proof tests in recent years has made it a rather risky business'. Note, no anecdotal or otherwise reports of specific failures at 162mm's. I think other options could be reasonably guessed at.

"It might be that 'testing' downstream of the forcing cone is intended to exceed stated proof pressure at 17 and 25mm's."

It depends what you mean by that.

If you assert that proof chamber pressure is being applied to the 162mm point, no. Each barrel would blow up.

If you mean they are using overall hotter proof loads to assure the 162mm test spec is being met, perhaps.

The rules of proof are fond of the term 'at least' so you really don't know what The Masters intend to do to your gun, do you?

There is certainly nothing wrong with establishing your own lower service pressure, as Larry and many of us do, in lieu of risking some sort of reproof official or otherwise.

Like Miller, I'm glad we have that option.

But then I'm not in the business of selling guns.

The Birmingham Proof House was established by an act of British Parliament. Don't their policies and actions speak to their intent?

I had Toby restore an Edward Lang hammer gun for me. I knew the left barrel was honed beyond 8 thou (out of proof), when we started. It needs reproof prior to sale.
Here is the thing. I wasn't going to sell it. I didn't want to risk my gun at the proof house. My barrels are plenty thick (+32 thou). It is still out of proof in the left barrel. I bought it with a big dent in the left barrel. I raised the dent. I then used it to practice browning. It came out great. So, I shot it. It shoots great. It needed the left firing pin sorted out as the nipple was prone to fall out. (puns expected)
I now have a 30" E. Lang hammer gun with IC/Mod chokes. It is a a great gun.
At my request, Toby did not submit the gun for reproof. This was my choice as the owner.
I would never offer this gun for sale in the US without the disclaimer that it is out of proof. It's a keeper.

Joe

Too metaphysical for me craigd.

I just spew piffle from a country that lacks proof legislation.

Joe, wardrobe malfunction?....Well, you knew it was coming...Geo