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Thread: Saigas and C.I.P. specifications

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    Gunco Regular mrtank's Avatar
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    Default Saigas and C.I.P. specifications

    Use any of the data or ideas in this thread at your own risk. By continuing to read this thread you acknowledge that you and only you are responsible for your own actions and the repercussions those actions may entail.

    The saigas are proofed and stamped by the proof houses. Therefore they should be held to the C.I.P specifications.

    7.62x39, 5.56x45, 5.6x39, 5.45x39, 7.62x51, and 9x53R. Both 7.62x51 and 9x53R seems to be using the one side bulged trunnion, but we can't be sure.
    I also threw in 7.62x54r, 6.5x52 Carcano, 6.5x54M.-Sch., and 6.5-284 Norma into the charts for comparison.

    Edit removed 7.62x54r data too many diffrent pressure listings, but still dosn't effect things in regards to the 308 Vepr.
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    Last edited by mrtank; 12-14-2010 at 03:25 PM.

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    Gunco Regular mrtank's Avatar
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    In the calculations I used ether the max cartridge diameter or the chamber diameter, what ever one was largest. I did this to reflect The kind of pressure that the bolt would experience with a case head separation. All of the calculations are setup in that manner. Actual bolt thrust will be less given the area on the inside of the cartridgeis less than what I am using, the drag between the case walls and the chamber also will reduce the force on the bolt.

    Based off of the calculations the 7.62x39 has the most Bolt force of the Saigas with the standard trunnion.
    Of the bulged trunnion the 7.62x51 has the larger bolt thrust even thought he 9x53R has a larger case head.

    The 6.5x52 Carcano is actually under the amount of force of all of the standard trunnion Saiga calibers, and the 6.5x54M-Sch. is a little over the 7.62x39 for force on the bolt.

    The 7.62x54r is close but a little over the force of the 7.62x51. Note the PSL does not have any proof marks on it so we can't hold it to up in comparison. Though the VEPR 308 does have the proof marks and it is using the RPK74 trunnion and bolt. As far as I have found in my research it was the standard rpk74 trunnion and standard AK74 stile bolt. The AK74 bolt does have thicker lugs than the AKM bolt though.


    As I said before by reading this you take responsibility for any repercussions of the actions you take based on this information. I haven't rigorously checked over my calculations so I would recommend doing the calculations yourself if you are even thinking of doing anything with with the information I have posted. If anyone finds any errors please alert me to them.

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    TRX
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    Good work, Tank!

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    Gunco Regular mrtank's Avatar
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    Thanks TRX. The C.I.P. numbers for the .260 Remington are the same as the ones I used for the 7.62x51, and they list the 30-06 with lower pressure than what they list the 7.62x51. I also didn't include the 8mm Mauser since I found information a while ago that lists the M75 sniper ammo as having a max chamber pressure of 2940 bar. I just noticed the pressure they list for 6.5x57 is the same as what they list for the 7.62x54r, and the 6.5x57 has a smaller case head so lower force on the bolt.

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    Happy Camper hcpookie's Avatar
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    I'm always interested to see this kind of information!

    I'm at work so forgive me if this is a 'duh' moment, but what sources are this data? Is this data you collected, or am I understanding that since it is proofed, these numbers are 'proofed' for these actions? ... meaning the numbers are published by the CIP?
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    Gunco Regular mrtank's Avatar
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    They were at one time published. The information that I list is from a data sheet from C.I.P. from 2007. They had a download link on there web page before they started there restructuring.... Some of the information involving rimmed cartridges is here. http://www.intermin.fi/intermin/imag...e/TABIIcal.pdf

    This pdf has information about there proofing procedure and the proof marks by country.
    http://www.europarl.europa.eu/hearin...o/genco_en.pdf

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    Gunco Regular allesennogwat's Avatar
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    Note that when CIP switched from copper crusher to transducer measurement they messed quite a few cartridges. First Lapua even says on their website the CIP copper crusher pressure was correct for 338 Lapua but the CIP transducer pressure is overpressure. Note that in the old CIP numbers 30-06 was higher than 8x57 and 8x57 was higher than 7.62x54R. Now all three are equal! The CIP numbers for 7.62x39 and maybe 5.45x39 look too high. I can't find the CIP copper crusher numbers for 7.62x39 and I don't think there are any for 5.45x39 from CIP. I think CIP standardized 7.62x39 shortly before changing to transducer. The military numbers are lower for 7.62x54R, 7.62x39 and 5.45x39 but that may be due to the method or placement. The 7.62x54R = 8x57=30-06 really sticks out but I wasn't sure to question it until I saw Lapua's website and what Lapua had to sy about the CIP transducer pressures for 338 Lapua. anybody have the early copper crusher CIP numbers for 7.62x39? I have them for 7.62x54R, 8x57 and 30-06.

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    Gunco Regular mrtank's Avatar
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    The story on Lapua's page says the .338Lapua Magnum should have a pressure of 42000 Bar, that coincides with what is in the C.I.P. data sheet I have from 2007. It seems they fixed at least that caliber. On the 07 sheet it is showing 7.62x54r and 8x57 IS at 3900 bar, 30-06 at 4050 bar, and 308 Winchester at 4150 bar.

    With the information I am doing back of the envelope rough calculations of the bolt thrust. I can plug in some different chamber pressures and the inside case dimensions if someone wants to section some cases.

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    Gunco Regular smartbomb's Avatar
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    i built a small javascript app that calced bolt thrust and charted them vs other calibers.

    here
    al gore is full of carbon enriched shit

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    Gunco Regular allesennogwat's Avatar
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    Quote Originally Posted by mrtank View Post
    The story on Lapua's page says the .338Lapua Magnum should have a pressure of 42000 Bar, that coincides with what is in the C.I.P. data sheet I have from 2007. It seems they fixed at least that caliber. On the 07 sheet it is showing 7.62x54r and 8x57 IS at 3900 bar, 30-06 at 4050 bar, and 308 Winchester at 4150 bar.

    With the information I am doing back of the envelope rough calculations of the bolt thrust. I can plug in some different chamber pressures and the inside case dimensions if someone wants to section some cases.
    I was referring to this information in the Lapua 338 Magnum story.

    Lapua: Story of Lapua Magnum

    The new cartridge was designed for over 4000 Bar pressures. The original pressure definition based on the deformation of the copper pellet method - the crusher method - was specified in the beginning into 56000 CUPs (about 3900 bar). When CIP moved to the piezo transducer period, a mistake was made somewhere resulting in the pressure medium for .338 Lapua Magnum to stay in the 4700 Bar level, even thought the correct level is in the 4200 Bars.

    Maybe they have corrected 30-06. It's still a bit odd 7.62x54R is equal to 8x57 which was only about 3 percent lower than 30-06. In the old crusher number 7.62x54R is lower than than 8x57. In the Polish military testing of their reference cartridges, the pressure limit is slightly higher than 7.62x39 but the reference cartridge measured slightly lower than 7.62x39. I know it's higher than 303 British but full power 8x57 pressure seems a bit much.

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