Wondering ?????

[Drew Hause]

Craig: Austria is a member of The Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives
http://www.cip-bobp.org/homologation...idge_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” transducer pressure
Service 1050 BAR = 15,229 psi
Maximum statistical individual pressure 1200 BAR = 17,405 psi
Magnum proof 1320 BAR = 19,145 psi

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.

[C.O.B.]

I spoke to Steve last night and the barrels and chambers were to the original specs regarding wall thickness and chamber length. These barrels were not honed in any way. The bulge is approximately at 2 3/4 inches and the chambers are 2 1/2. This probably occurred by using a high pressure 2 3/4 inch shell in a gun chambered for 2 1/2 inch shells.

As a note of possible interest a friend of mine was shooting his Fox Sterlingworth when the barrel burst at the chamber. The previous shot went off without any problems and the target was broken. Sometimes things just break.

[Drew Hause]

Thank you Rich. Could you please inquire as to what the wall thickness at the end of the chambers, at the forcing cones, and at the point of the bulges measures? That information is quite important to those of us who chose to use Pattern Welded barrels, and have followed this thread with great interest.

Does The Parker Pages have a Mechanical Specification Drawing with the "original specs" for wall thickness by gauge?

[Sheepherder]

Has anyone thought of the possibility of shells loaded (or re-loaded) with STEEL shot? Both barrels, with the same problem, at or about the same time? It's got to be a load/barrel relationship issue. Not an obstruction.

[OH Osthaus]

Originally Posted by Hal Sheets

Has anyone thought of the possibility of shells loaded (or re-loaded) with STEEL shot? Both barrels, with the same problem, at or about the same time? It's got to be a load/barrel relationship issue. Not an obstruction.

In that case -I believe the ring bulge would be at the chokes. Not the forcing cone

[Fishtail]

Well.....I guess that settles the question of who the guilty party is once and for all. If I were in his shoes, I wouldn't go around advertising what I had done....or at least I would accept responsibility for it.

[Bill Murphy]

Drew has a good request, but there is some stretching when a barrel bulges or ruptures and you have to be careful where you take your measurements.

[C.O.B.]

I'll try to get the measurements requested. Steve is in Montana currently.

[Drew Hause]

Thanks again Rich. Please also confirm the chamber length and bore measurements just proximal to the bulges.

The issue is not to dispute Steve's statement, nor to assign blame, but to reach some conclusion as to the cause of the barrel failure.

It is my sincere hope that this will not end as most posts regarding barrel/gun failures, at least on doublegunBBS and trapshooters.com, have ended; with no definitive, or at least learned, explanation. Modern guns sent to the maker for a failure analysis and metallurgical study disappear, and when litigation is involved, details of any settlement are made confidential.

Something like this would be definitive



To be clear, I have found no Specification Diagram for wall thickness from any turn-of-the-century U.S. maker. That information would be invaluable to those of us measuring wall thickness and providing an opinion regarding originality, and safety.

[edgarspencer]

This got my curiosity up, so I measured a set of 0 frame barrels from a 16ga. DH
I was surprised at that variation.