Pressures....

Discussion in 'The Ammo & Reloading Forum' started by GMFWoodchuck, Nov 15, 2008.

  1. GMFWoodchuck

    GMFWoodchuck New Member

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    I would swear I had asked this question But either I just can't find the thread or I never actually posted it.

    I understand why there are maximum published loads and why the the pressures so different. I would never expect my grandfather's win '94 to handle the kinds of pressures that my Savage 12 .22-.250 can handle.

    However, if I have lets say two modern Remington 700's. One is chambered for a 22-250, the other for the 30-30. Could I load the 30-30 to the same kinds of pressures (not that I would because of the lack of published info) being that the guns are basically the same other than the caliber itself and still be "safe"?
  2. Bindernut

    Bindernut Well-Known Member

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    Simple answer...no.
    The 30-30 case is not built heavy enough to handle the higher pressure.
    Sticking with your theoretical situation...
    The 30-30 brass is thinner than the 22-250 you're comparing it to and the higher pressure will cause the brass case to fail. The rifle action is the same and will not be the failing point, but if that brass case splits/separates then that hot gas will also find it's way out the back of the action...usually right near your face & hands. Not a good thing! :D



    Until you get into the realm of wildcatting and have a good understanding of all the variables involved it's always best to stick with published data. There are some cases and actions that you could get by with overloading to "+P" type pressures when used in a modern rifle (.257 Roberts is one that pops to my mind at the moment) but it's real shaky ground and you're putting yourself and your rifle into a situation where the margin for error is very thin.
  3. GMFWoodchuck

    GMFWoodchuck New Member

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    I didn't think about the brass being thinner. That makes sense.

    Thanks. I never wanted to do it, I was just curious. And I have no real interest in wildcatting anyways. It seems like that there is so many different standard calibers that I have no real need to wildcat. Any possible need that I could imagine having has already been fulfilled by a standard cartridge. Especially as of late with the short mags, the "super" mags and the bench rest rounds.

    Don't get me wrong, I understand why people love it. It's the same as people playing with their cars/trucks and anything else they own. But I can't really justify spending thousands on top of thousands of dollars on a .22-.250 akley improved (or whatever) when my 399 dollar .22-.250 Savage 12fv/scope combo from dick's is making one hole groups (so small that I thought the follow-up shots were missing the paper altogether at first) at 100 yards with the Remington UMC ammo.

    Maybe I can get my wife to want a specialized bench-rest rifle in a wildcat caliber......



























    Yeah, right. Fat chance. lol
  4. steve4102

    steve4102 Former Guest

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    With the two examples you listed 30-30 and 22-250 the answer is no as BN pointed out. However there are quite a few cartridges that can be run at modern(higher) pressures.

    The 6.5x55 is one example of a cartridge that is loaded down to accommodate some older Mauser type actions. There is no reason that a modern rifle chambered in 6.5x55 has to run at the anemic pressures of and old military action. Some powder manufactures have come from the dark ages and now publish data for the 6.5x55 at 55-56,000psi, while others are still publishing old data that runs at 45-49,000psi.

    The 30-06 is another example. No reason why the 30-06(60,000psi) can't be brought up to 270 Win(65,000psi) pressures in a modern rifle.
  5. LDBennett

    LDBennett Well-Known Member

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    In general it is not a good idea to vary from published data for any cartridge. I recommend to NOT try it.

    But there is more to it than just pressure. The cartridge develops a pressure, pounds per square inch. The larger the area of the case's base that pushes on the bolt face of the gun then the greater the force on the bolt face and locking lugs. It is the force that breaks guns, not the pressure. That is, it is a pressure operating over an area. A larger area for the same pressures equals more force on the action of the rifle.

    If you want a hotter cartridge just buy a bigger gun. Hot rodding a cartridge in general is not a safe thing to do. It is possible to do but you must understandc the risks, have health insurance, and have liability insurance.

    LDBennett
  6. Mark

    Mark New Member

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    I went through this just the other day.

    The 8MM Mauser has a SAMMI pressure of 45K. With a .473 bolt face that gives about 8K of bolt thrust. Increase the pressure to 65K, and the bolt thrust goes to (short of) 12K. Open this bolt face to .535, and bolt thrust goes to almost 14K, with a 65K pressure.

    Mausers are tough, but they were not designed to handle this thrust/pressure. Just because someone has done something before, does not make it a good idea.

    "The magic always ends somewhere".

    Mark
  7. younggun28

    younggun28 New Member

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  8. muddober

    muddober Active Member

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    If I understand you question can one load a 30-30 to the same pressures as a 22-250 assuming you were going to shoot them both in a 700 Remington chambered for each respective round? If that is question the answer is YES and the thickness of the brass of a modern 30-30 case is of sufficient thickness because the case does not really see any pressure that can split or rupture it any more than it could the 22-250 because it it fully contained by the chamber of the rifle just as is the 22-250. No brass can see much pressure at all assuming it has a place to flow too which can be seen in some revolvers with sloppy cylinders causing bulged cases with even low pressure loads. Back to your 30-30 case, I load for many different cartridges including a 30 Herret which uses a shortened 30-30 or 32 Winchester Special case and my most accurate loading is at least a 55,000 psi loading because it flattens primers just as bad if not worse than my 25-06 loading that according to the manual is a 56,000 psi loading. I have while working up loads for my Herret blown some primers and other than damage to the primer pockets the cases never split, bulged or ruptured. I will admit blowing primer pockets is not prudent but anyone working up loads for as many different cartridges and as long as I have has probably done it as well if they would admit it.
  9. muddober

    muddober Active Member

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    Mark: I agree that your math is 100% correct but I suggest with all due respect that perhaps your theory is wrong. While I don't have a bolt from a Mauser handy right now I am going to guess that between the two locking lugs on the bolt they would have a total locking surface area of at least .333 of an inch. At 14K of thrust over that area would be equal to only 42,000 psi making the bolt not the weak link as you suggested. If I am off on my guess and it is even less at .250 it would still be only 56,000 psi which is still tolerable in my mind. Please comment and again I say this with all due respect and just having fun.
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