Loading pressures

Discussion in 'Reloading' started by muleyman, Apr 23, 2008.

  1. muleyman

    muleyman Well-Known Member

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    I have been reloading for some years now and have pretty much always followed maximum recommended loads. In looking back through various loading manuals, they seem to have started going more milder in the max loads. What are some obvious signs of over pressure that appear on cases.
     
  2. old_heli_logger

    old_heli_logger Well-Known Member

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    On the cases:
    1. overly flattened or loose primers
    2. soot around the primer (like it is leaking)
    3. bolt face embossed, showing your extraction groove

    Also watch for a hard to open or a sticky bolt

    Good luck and be careful
     

  3. Jim Oliver

    Jim Oliver Well-Known Member

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    High pressure signs........

    The indications mentioned by old_heli_logger are what I might expect to see with what I would call "very high" pressures.

    Other signs will be case expansion in front of the extractor groove (most folks don't have the right tools to measure this), unusual case length growth; these signs compared to factory loads fired in the same gun.

    Another earlier sign would be primer pockets getting loose after only 3 or 4 loads. Some shooters/reloaders are willing to accept early loose primer pockets, and the increased barrel wear that goes with it, for a bit more velocity.............

    I think some of my loading manuals have pics and text in the front of the book that show and describe some examples of "stressed" cases.

    Cheers,
    Jim
     
  4. steve4102

    steve4102 Well-Known Member

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    This is a quote from the Administartor of another handloading forum. Any thoughts?

    "Well again sadly if you take all you know of pressure signs and all the rest of the reloaders of the world combined know about pressure signs and put it all in one bucket you won't have enough knowledge to buy a cup of coffee.

    Those old wives tales of what to look for are a load of malarky and have been stated to be such these days by just about every known magazine writer in the business. I think they are finally coming around to the reality that if they keep on BS'ing folks that those signs have meaning they just might be on the losing end of a lawsuit some day.

    Every test I've seen run comparing al those "pressure signs or indicators" to real world pressure data show them to be meaningless. You might see signs of high pressure even with the minimum starting charges or you might not at blue pill proof load levels. Believing you can tell what is safe in that matter is a recipe for disaster and it's time folks begun realizing it."
     
  5. Jim Oliver

    Jim Oliver Well-Known Member

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    Steve4102,

    Are you saying that you think it is OK to ignore these indications of high pressure?

    If not, then just what do you mean to say?

    Thanks,

    Jim
     
    Last edited: Apr 23, 2008
  6. ss7mm

    ss7mm Writers Guild

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    Thanks but I think I'll keep my little bucket that has the knowledge of those I trust plus all of my years of experience in it. And, I've also got all of the coffee I'll ever need.:) It's not that big a bucket but it has gotten me by for a lot of years and has been especially useful when dealing with wildcat rounds that have no factory info available anywhere as well as every factory round I've ever reloaded for.;);)
     
  7. steve4102

    steve4102 Well-Known Member

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    No I do not agree with this statement. I would like to know what you guys think about this kind of logic? I have seen some of the writings by "Gun Writers" on this subject and I find it disturbing. If these signs that we have all used for years are now nothing more than "Old Wives Tales" and "Reading Tea Leaves" then what's left? I duno.
     
  8. Varminator 911

    Varminator 911 Well-Known Member

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    What about loading to velocity goal

    I don't know the answer here. But what about loading to a velocity goal. True you have to know a reasonable and safe velocity to use this approch. But I've gotten the idea that this might be useful. It is the approach that GS Custom uses for their bullets. Kinda seems to me it would only work for known powder/cartridge/barrel length combinations.

    I've also gotten the impression that many on this forum consider a load safe if the case life is acceptable and primer pockets stay tight.

    Would Quickload be any help here?
     
  9. eddybo

    eddybo Well-Known Member

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    A chronograph can tell you a lot about your pressure IMO, but there isnt any way I am going to ignore any of the traditional pressure signs trying to reach a published safe velocity. I am not saying that you are advocating that.

    I think the safest approach would be a dual approach with the use of a chronograph along with watching for traditional pressure signs. I do not care if it is like reading tea leaves or not.

    I have seen a couple of instances where I was undoubtedly getting very high pressure but could see no signs on the case. A chrono would have helped me realize I was above max. I have also seen instances where I was a good bit below advertised velocities and readily saw pressure signs.

    Until pressure testing equipment becomes readily available and cheap I guess we are just going to have to rely on whatever means we have to discern dangerous pressure, including Quickload which I find invaluable.




     
  10. marchboom

    marchboom Member

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    Not all of us have access to a ballistics lab so we have to depend on accepted pressure signs, reloading manuals, chronographs results and years of experience.

    But if anything is a danger to someone who handloads, it is "pet loads". I hate that term. You see shooters on this forum, and others, asking for a pet load for a certain caliber. Making a suggestion on the components that one uses and has good luck with is one thing, but if posters care about their fellow shooters they should refrain from indicating the load charge. There are handloaders who will blindly follow that recipe exactly. Sometimes with dangerous results.
     
  11. dwm

    dwm Well-Known Member

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    I am no expert on this, but I have learned that there is more than one possible root cause for pressure signs.

    A load may be completely reasonable and safe, but the headspace may be wrong. This will cause pressure signs and can be frustrating.

    A load may be completely reasonable and safe in one gun with a long throat/freebore, but dangerous in another gun if it has a short throat/freebore and the bullet gets jammed way into the lands.

    Also, in some cartridges, not enough powder is also dangerous.
     
  12. eddybo

    eddybo Well-Known Member

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    I have heard this and understand it to be true but can you give any info on this. I am thinking about treading on new ground with a subsonic load in 30/221 and am trying to find out everything I can before I risk my gun.
     
  13. P KUNDA

    P KUNDA Well-Known Member

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    I load every cartridge to the max, but

    Because I'm the one who is holding the rifle I back off one grain everytime an excesive pressure signs appear. I rather have all my fingers, then a 100fps more velocity.

    Peter
     
  14. big wally

    big wally Member

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    Surely any excess pressure sign is a advance warning of impending doom and should be investigated.
    An increase in case size just ahead of the crouve or rim is an indication of excess pressure or an oversized chamber.
    An increase in case length every shot could be an over pressure load or a badly lubed or over size expander ball draging the neck out.
    A sticky bolt that is perfect with other loads and factory loads ( usualy well under max ) is a sure indication of an overload.
    A pierced primer could be a bad fireing pin or the wrong primer for that load but usualy a over hot load.

    Lots of re-loaders think that once a load has been formulated with a batch/lot of powder that every tin or bottle of that same powder will be identical!!!
    Dont be stupid evbery batch of powder could give higher or lower pressures than the one you have just finished.
    I have bought three batches/lots of Viht N 120 to fuel my 17A/H And i run it between 3,550ft/sec and 3,650ft/sec because thats my accuracy node.
    THE DIFFERENCE IN THREE BATCHES TO GET TO THAT VELOCITY WAS 0.6GR.
    And that is a hell of a lot in 17A/H cases.

    Work up a load from 10% less than the good one you have been loading with every componant change espessualy the different batch/lot of powder.
    Dont ever try a load that someone has loaded for their gun even if the calibre is identical

    Big Wally