Proofing Marks Question -Parker Hale-

I am not sure about the 2.500 - they often marked the case length, but SAAMI sets the case at 2.540, so can't be sure. The actual "proof" mark will be a mark with crossed swords - with a letter before and after the X and sometimes a letter or number below. The letter before and after give you the date that the barrel /action / bolt was pressure tested - go here to see the table: http://www.hallowellco.com/proof_date_codes.htm I often have to use a magnifying glass to see the letters.
 
Hoping that I can now add links to photos, I am very much a newbie here.
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Okay - the British proof mark, which gives you the date is that last symbol on the second line - I think the letter to the left of the X is "V" - I can not make out what letter is to the right. If it is a "C" on the right, then the rifle was "proofed" in Birmingham in 1994. And it was proofed at 19 tons per square inch pressure, just like it says... I happen to have an older BSA rifle, also nominally in 270 Win, also marked 2.50", also proofed in Birmingham, but it has unusually deep grooves - .282" or more - and literally shoots 5 inch "groups" at 25 yards!!! On mine, the proof code is B X B, so that should mean 1951 proof year.
 
The gun has been in the family since 1974 or '75. I refinished it in the early 80's and my father sold it to me for $100 per deer around 1992. The damned thing cost me $1800, dad never pushed collecting the debt though!
 
From the dates you gave, I must be seeing the letters incorrectly. Can you tell me what those letters are on each side of the Crossed Swords / Crossed Pennants? If that letter to the right is "B" and that is a "V" to the left, then that was a 1970 proof, as per that table.
 
Apparently the symbol below the cross swords identifies the particular inspector who did the proof test, but I have not seen a list how to identify who that was.
 
Shucks, I've had many problems with this rifle using custom ammo loaded to max spec. A friend of mine and I have become suspicious that the custom loads need to be a COL @ 2.5 and no more rather than the accepted to 2.540. I am almost positive, though not sure, this receiver and barrel were built before SAAMIS standards were accepted industry-wide.
 
Well, our rifles were made in Britain, and the 270 Winchester was an American invention, and SAAMI is an American voluntary association that sets standards - even American producers don't HAVE to comply with SAAMI - there is no law saying that they must. That, for example, is why any person can screw a barrel into a receiver and sell it, without having it proof tested at a government facility like it must be in Europe. I have no idea at all whether Britain, Parker Hale, or BSA ever "accepted" SAAMI at all, or whether they made up their own standards for the 270 Win. But the cartridge was first offered for sale in 1925, at least in the US of A. There is a European standards organization - C.I.P., whose standards have the force of law in the countries that adopted the C.I.P. They are similar, but not always the same. For example, SAAMI named a German cartridge the 8x57, which is not the name it is known by in Europe, and chose to set the pressure levels much lower than CIP does, for the same cartridge.

Before I get much further with this BSA challenge of mine, I intend to do a cerrosafe casting of the chamber and see what is going on in there...
 
Looks like they're specifying .270 Win based on 30-06 case length as opposed to 30-03 which is the basis for the .270. Likely a simple anachronism without practical value excepting that it could mean the rifle could shoot better with shorter bullets and ammunition, as the 30-03 revolved around a 220 gr bullet. Some proofing also measures chamber deformation. Either way European arms standards are historically very high and guarded jealously so you're in good hands.
 
Potashminer said:
Okay - the British proof mark, then the rifle was "proofed" in Birmingham in 1994. And it was proofed at 19 tons per square inch pressure,.
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what I don't understand about British proof pressures is that they seem to be a lot lower than the operating pressure of the cartridges. If the 19 tons is metric tons, that is about 42000 psi while the average pressure given for a 270 Winchester is 65,000 psi

cheers mooncoon
 
I agree about the units of measure. Even using "long ton" at 2,200 pounds, that is still only about 42,000 psi. I had read their procedure required greased cartridges, and that they measured an axial load, rather than a radial load. But, since their units are not psi, they may have worked up an entirely different standard than we commonly see. I have a Parker Hale (might be a 1200) with T X B (1968) BNP proof that says "19.5 tons per [] inch" and 2.56" chambered in 308 Norma Magnum
 
mooncoon said:
what I don't understand about British proof pressures is that they seem to be a lot lower than the operating pressure of the cartridges. If the 19 tons is metric tons, that is about 42000 psi while the average pressure given for a 270 Winchester is 65,000 psi

cheers mooncoon
Click to expand...

Different methods of proofing are used the measurements of PSI may be using the CUP method which does give lower measurements than the methods used for SAAMI. It comes up all the time in the .308 verses 7.62x51mm disscusions
https://en.wikipedia.org/wiki/Copper_units_of_pressure
 
Here is a posting just found on another forum - sounds plausible, but no references to sources given:

"18.5 tons or tsi (45,000 cup or 49,000 psi U.S. measurement) is the normal operating chamber pressure and "NOT" the pressure the rifle is proofed at, the Enfield was proofed with two proof cartridges at a pressure between 23 to 25 tons or tsi. One "DRY" proof round was used to proof the barrel and one "OILED" proof round was used to proof the bolt and receiver. The oiled proof test round was used to seat the locking lugs and bolt head, after proofing the Enfeild rifle was checked with a .067 headspace gage. If the bolt closed on the .067 gage the rifle failed proof testing due to excessive bolt lug setback. Please note that any oil or grease in the chamber or on the cartridge case will cause twice the amount of bolt thrust to be delivered to the bolt face. The oiled proof round also simulates combat conditions like firing in the rain with wet ammunition or water in the chamber and bore."
 
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