90,000 psi loads ?

Discussion in 'Long Range Hunting & Shooting' started by 460or338, Jun 22, 2010.

  1. 460or338

    460or338 Well-Known Member

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    I noticed some weatherby loads dont have a saami/sammi pressure.and the weatherby action is proofed to 250,000 psi .might be why no one else chamber their calibers .any one care to share waht they know about high pressure calibers 70,000 psi+?.will the brass give out before the chamber ?
     
  2. GMBshootingclubM60

    GMBshootingclubM60 Well-Known Member

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    The steel yields at 100,000 or so, that would be the point where the gun locks up. It's only momentary though, so maybe it would survive?

    I asked a question in another thread about the Weatherby having a freebore to drop the initial pressure peak.
     

  3. J E Custom

    J E Custom Well-Known Member

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    They are SAAMI spec but with lots of free bore.

    Brass will not take much more than 70,000 psi and last no mater what brand it is.

    You are right about not shooting Weatherby ammo in a non free bored rifle, Even if it
    is a Weatherby cartrige. The pressure will be to high and will probably blow the primers.

    This is the way Weatherby gets the high velocity.(More powder with no more pressure)

    Free bore does not hurt accuracy as long as the rifle is set up correctly. just like a belt.

    J E CUSTOM
     
  4. Chas1

    Chas1 Well-Known Member

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    What is meant by "the gun locks up. It's only momentary though"?
     
  5. royinidaho

    royinidaho Writers Guild

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    I have at least one shot @ greater than possibly 80,000. Had a bit of a powder bridging problem. Normal loads were running higher than 65,000 if the RSI was calibrated properly.

    Hammered the bold open. Primer had a 64th or so space around it.

    Went back to ball powder and never looked back.

    The pressure hurt nothing but the case.
     
  6. GMBshootingclubM60

    GMBshootingclubM60 Well-Known Member

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    Roy, did you magnaflux the bolt to see if there were any cracks at the base of the lugs? You may have a permanently weakened bolt?

    Railroad couplers (knuckles) many times will show signs of a prior overstress when they break... at the same spot.
     
  7. GMBshootingclubM60

    GMBshootingclubM60 Well-Known Member

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    What's an RSI? Roy's stretch indicator? (smile)
     
  8. J E Custom

    J E Custom Well-Known Member

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    Now thats funny !!!!!!!!!! I don't care who you are.

    J E CUSTOM
     
  9. royinidaho

    royinidaho Writers Guild

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    No I didn't magna flux it. Just kept on shootin'.:rolleyes:

    RSI Inc. Recreational Software Inc. Ballistics Software, Chronographs & Pressure Instruments For Shooters

    Actually Roy's Stretch Indicator is a piece of type writer correction tape that has been typed on. Its wrapped around the chamber then distortion of the lettering is measured. Hmmmmm, I wonder if that would actually work?:D
     
  10. GMBshootingclubM60

    GMBshootingclubM60 Well-Known Member

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    I went to RSI and read the story of the peak pressure happening twice. The second peak was WAY high.

    It would seem to me that if you put a second stretch gauge a few inches down the barrel from the chamber gauge, it would measure the second peak only.

    That is, the chamber gauge would have the double hump and the gauge farther down the barrel would only have a single hump, the secondary peak, if it existed.
     
  11. royinidaho

    royinidaho Writers Guild

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    I've seen the double hump trace on my 338 RUM but it was way smaller than the first.

    (No observable stretching on "Is". Was observable on "E"s):D

    Was told it was common several cartridges.

    I've heard of reflecting shock wave theory. Suspect this is what blows up 22-243s with low loads of 4831. Either way I solved that potential problem by never shooting that cartridge.:)
     
  12. GMBshootingclubM60

    GMBshootingclubM60 Well-Known Member

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    Is this why some of the 50BMG loaded way back when had a handful of long, noodle-looking strands of powder, instead of the granules they use today? Perhaps this would avoid the 'explosion instead of burning' problem?