Mathematical Challenge re: CE 399

[David Josephs]

Dave

Right off the bat, Frazier couldn't do math to save his life. I've proven this several times. 6.65 mm does not equal .267", 6.65 mm = .2618". A 6.5 mm Carcano bullet is actually 6.8 mm in diameter, if made to the Italian military specs. You may just have unwittingly uncovered the proof I have been seeking for so long that proves the Western Cartridge Co. 6.5mm Carcano ammunition was loaded with hopelessly undersized bullets that would have destroyed the accuracy of any shot made from that rifle.

Uh, ok. hope I helped...

found this interesting...
Take care
DJ

Mr. MCDONALD. Did you compare the FBI test bullets with your own test bullets that you recently fired out of 139?
Mr. BATES. Yes, we also made a microscopic comparison of that.
Mr. MCDONALD. And what did the comparison show?
Mr. BATES. The results of this examination indicated that we could not determine whether the FBI test bullets were, in fact, fired from the rifle, CE-139

Mr. MCDONALD. Would you have expected that result considering the number of times that CE-139 has been fired over the years?
Mr. BATES. Yes, we would have.

Mr. BATES. The panel, including myself, conducted comparative microscopic examinations of CE-399 against both of the FBI test bullets, CE-572.
Mr. MCDONALD. What findings did you make?
Mr. BATES. As a result of our comparative microscopic examinations, it is our opinion that the bullet, CE-399, was fired through
the same firearm barrel that fired the FBI tests, CE-572.


Mr. MCDONALD. Can you determine the caliber of a rifle merely by looking at it?
Mr. LUTZ. No, you cannot, because many times the differences in caliber is a few thousandths of an inch. The difference between a 6.5-millimeter Carcano bullet, or the muzzle, the barrel itself, the inside diameter, and the difference between it and the 7.65 German Mauser is only a few thousandths of an inch, 40-some thousandths of an inch difference. We are speaking of .265 inches in diameter for the 6.5 Mannlicher-Carcano bore diameter and we are speaking of .313 inches of diameter for the Argentine Mauser made in Germany.


Frazier converted wrong... but he does say .267"... so I guess someone would have to actually measure the ejected cartridge's bullet...

http://personal.stevens.edu/~gliberat/ca...emary.html
The primary loading for the cartridge throughout its service was a 162-grain full metal jacket, round nose bullet measuring nominally .267" diameter
The CIP minimum specification diameter for the 6.5 mm Carcano barrel is .256 in / 6.50mm. The groove diameter of the barrel is where a considerable amount of ignorance arises in the Carcano rifle. Nearly every other 6.5mm caliber has a groove diameter of .263 - .264".
The exceptions to this are the 6.5 X 54 MS with a .266" groove and the Carcano with a CIP minimum specification groove diameter of .2677" / 6.80mm. I do not know what the production tolerances were for the Carcano, but based on my knowledge of current rifle manufacturing practice a tolerance of at least +.001" would be used for these dimensions. I have slugged the barrels of approximately 20 different types of Carcano rifles from 3 different manufacturers and have found barrel diameters in good condition rifles typically running from .2680" to .2690"


6.8mm = 0.267717"

6.7818mm = .267"

6.731mm = .265"
6.65mm = 0.261811"
6.5mm = 0.255906"

and he's wrong here too, kind of. it's 6.5278mm which does round down to 6.5mm
Mr. FRAZIER - That is the same as .25 caliber. Such weapons in the United States as the .25-20 Winchester, .25-35, the .250 Savage, and the .257 Roberts, are all of the same barrel diameter, or approximately the same barrel diameter. So a decimal figure of .257 inch is the equivalent of 6.5 mm.