Pressure Signs.....

Discussion in 'The Ammo & Reloading Forum' started by AR guy, Nov 27, 2012.

  1. AR guy

    AR guy Member

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    Hey, I'm gunna go to the range this weekend and test out my test rounds (9mm) I made earlier this week. Besides looking how the gun functions with the rounds, cycles them in and out, accuracy, recoil. What other signs of pressure am I looking for? Am I looking at the spent rounds for anything? Excessive recoil? I just wanna know what I'm feeling (or looking ) for before things go south? Any recommendations?
  2. clepidus

    clepidus New Member

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    I wish I had some photos to illustrate this. Your manual should have a few pictures in it, I know my Hornady book does and I'm pretty sure Nosler does as well. I know I will miss a few but starting from the head:
    Flattened Primers or primers that have come out.
    Bulges
    Case head separation
    Cracks and burns
    Those are just the obvious ones that pop into my head. With a straight wall case like your 9mm it should cover most signs.
  3. aa1911

    aa1911 Active Member

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    primer flattening is something I always check for sure. If I see that I know I'm pushing it!

    more likely to see that in rifle calibers though, if you see that in your pistol rounds could be bad news.
  4. AR guy

    AR guy Member

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    Im not home rite now but what do you mean by flaten primer? like its being sucked down in the pocket flat or being pushed out flat? i have the speer #14 manual. when i get home later ill look for pictures.
  5. jim brady

    jim brady Active Member

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    Look at your seated primers (before you fire the rounds) and you will notice how the edges of the primers are a little 'rounded over'. When you have higher pressure when firing, those rounded-over edges will become more flat.

    I tend to stay away from maximum loads in pistols AND rifles. All you need is accuracy and stopping power, and firing maximum loads only beats up your firearms for no reason - except maybe bragging rights. The one exception for me was when I developed a hunting load in my .30-06s - and the most accurate charge turned out to be near maximum.
  6. LDBennett

    LDBennett Active Member

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    AR guy:

    All fired primers get flattened to some degree.

    The way cartridges work is the firing pin hits the primer, setting the primer off, which eventually ignites the powder. The primer when it first ignites, pushes the primer slightly out of the primer pocket and is stopped by the bolt face. The gas pressure expands the case, pushing it back against the bolt face and reseats the primer. So the primer is propelled against the bolt face and then jammed hard against the bolt face as the cartridge case moves rearward under gas pressure to reseat the primer.

    The higher the pressure the cartridge case works at, from 10,000 psi (some pistols) to 60,000 psi (some rifles), the flatter the back of the primer is reformed. So primer flatness is not a good measure of case pressures (nor is the cratering around the firing pin impression on the back of the primer cup), as there is always some of it to some degree. About the only way to make use of the primer flattening is to compare it to a commercially loaded fired case.

    But if the primer is spit out of the case or the primer pocket becomes loose (you detect that when you try to put a new primer in the case at reloading time) or the head of the case separates from the body then you are way over pressure.

    The safest thing for pistol rounds is to load in the middle or to just above the middle of the manual's load range. If the gun operates at that powder level then the chances are the accuracy is better than at a full load and it is easier on the gun.

    LDBennett
  7. steve4102

    steve4102 Former Guest

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    Reading primers is a kin to reading tea leaves. They maybe be able to tell you something, determining "what" is the tricky part.
    Some primers will flatten out a little bit even at low pressure. This can easily be interpreted as a "flat" primer because it looks different than a primer that has not been fired.
    How to tell the difference? Is there any evidence of cratering around the firing pin strike? This is another sign of high/excess pressure, and might be a better index of excess pressure.

    I read this awhile back and I thought I would steal it.

    Think about this: Primers don't know what cartridge they're in.
    A small pistol primer in 380auto and a small pistol primer in 38 Super.
    The primer is too ignorant to know that it must flatten at 18000psi in the 380
    but wait until 36000psi if loaded in a 38 Super. It just isn't smart enough.
    Take that Winchester LP primer, good for both standard and magnum cartridges.
    How does it know you seated it in a 45acp, or maybe a 44 Magnum?
  8. aa1911

    aa1911 Active Member

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    ^^ well put

    various manufacturers also use different thicknesses in their primer construction, some are thicker than others, or so I've read.

    so the same load with different brand of primer could show different amount of flattening based on construction
  9. AR guy

    AR guy Member

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    Ok cool. everthing sounds good. Ill keep a eye out for the primer. Second of all I did not load max or come close. Being new and not knowing what to expect with reloads I started with 1 tenth under start and only went to the mid way point. I figured I can always go higher if need be. The primer issue seems like a tell tail sign that things are getting close or too much. But ill also concetrate on accuracy and recoil. Things will go just fine and ill get back with my findings. Thanks
  10. steve4102

    steve4102 Former Guest

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    This is not good. Do not go below published Min(start). Be very careful when shooting these below Min loads. A stuck bullet may be in your future. If a bullet gets stuck and a second round is fired over the top, KB.

    Start(minimum) means just that. Going lower can be just as dangerous as going over Max. I know it's only 1/10, but it is still not a good idea.
  11. AR guy

    AR guy Member

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    Thanks Steve4102 I never even gave that a thought. I got them all boxed up and seperated so ill just put those aside and take care of them. Yeah i dont want to get one stuck then fire another dont sound good. ill do just that take apart and salvage or redo. thanks.
    Last edited: Nov 27, 2012
  12. aa1911

    aa1911 Active Member

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    Stay within the published range! pushing a stuck bullet out of your barrel is no fun, ask me how I know...

    As long as your gun is in correct working order and you are not using abused brass, a middle of the road powder charge is not going to be the cause of a kaboom.
  13. AR guy

    AR guy Member

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    Thanks and not I dont want a bullet stuck. I just wanted to be safe, but I see trying to be too safe could be dangerous too. For now on im looking at both sides before I load. Thanks.
  14. shorter260513

    shorter260513 New Member

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    stuck bullets stink I had to beat one out of a 6in 357mag ruined a couple cleaning rods and a handfull of dowell rods before that sucker finally popped out
  15. LDBennett

    LDBennett Active Member

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    There is anopher problem with the minimum load in some semi-auto guns, as most 9mm are. There must be enough energy for the gun to cycle. Sometimes minimum loads will not fully cycle the gun. It will go bang but maybe not extract and eject the fired case. Or it may fire, extract, and eject but not pick up the next round in the magazine because the slide did not travel all the way to the rear. Or the gun may just jam in part of the cycle.

    A mid-range load is fine IF you do everything else perfectly, like use the correct bullet, and use the correct seating depth. You can then go from there up to no more than the Maximum load. But between the mid level load and the max load you may find a place where the accuracy is the best. You do not have to shoot the max load. It is harder on the gun than a mid level load.

    A load below minimum is dangerous because the results may be an explosion of the powder rather than a burning of the powder. The result can damage the gun and maybe you.

    LDBennett
  16. AR guy

    AR guy Member

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    LDB, So what your saying is with most 9mm's like mine I should stay between 2/3 and and max, just because the gun needs more power to cycle good. Ok that sounds good, but then would the powder have a factor in this? ( slow burn/ fast burn ). In some samples I made I used TG powder and my other samples I used WSF. Would it be safe to say that my TG is good because its on the fast/hot side and the WSF should be loaded more to the max load.
  17. LDBennett

    LDBennett Active Member

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    AR guy said:

    "Would it be safe to say that my TG is good because its on the fast/hot side and the WSF should be loaded more to the max load."

    Not necessarily.

    In my opinion you should be loading to the mid range of the load data to assure the gun will operate. It matters not whether the powder is fast or slow within the published data. Most manual data is tested to assure most all guns operate, even at the starting loads. But new guns have lots of friction and strong springs and may not operate with starting loads. Some never will. If you stay in the middle of the data you can be pretty sure the gun will operate correctly. Just don't load up hundreds and hundreds at any level until you are sure they fully operate the gun and are reasonably accurate. Never exceed the max load levels.

    We choose powder based on performance and maybe costs. With fast powders you use less and consequently you can get more shots per powder canister. I use W231 almost exclusively because it uses a reasonable amount (tiny powder charges as with Bullseye are more affected by 1/10 grain load variations which are just about the accuracy limit on measuring powder loads) and because I can use it in almost any pistol cartridge and because I can get more loads out of a powder canister. I choose to not use slower powders because of the economics. To be perfectly frank if I compared powders shooting un-rested I would find that any powder is more accurate than my shooting ability especially at my age. So why not save a penny or two. Also my Dillion powder measure likes ball or flattened ball powders better than flake or extruded powders.

    Now if it is power I'm after for magnum cartridges then I use IMR4227 or 2400 or AA #9, all very slow powders.

    LDBennett
  18. AR guy

    AR guy Member

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    Ok well understood. I will stay and keep my loads between start and max. And that's exactly why I bought the TG it was cheaper than most I saw. And I was also thinking about how much I could get out of a lbs. 7000 grains in a lbs so that's a lot of rounds. But back to the main question ok I got it and understand everything you said. Thanks. Honestly I'm glad you guys are here to help and answer questions or concerns and to stop us from doing something stupid that we might do. It's always good to have a good second opinion... Just my thought anyway.
    Last edited: Nov 28, 2012
  19. al45lc

    al45lc New Member

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    One of the Speer manuals had a short article on primer flattening, in short, loads at 20% OVER max were not visually different than 20% BELOW max in primer flattening.
    So the tea leaf analogy is spot on, IMO.
  20. steve4102

    steve4102 Former Guest

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    Personally, I do not like super fast powders like TiteGroup in high pressure rounds like the 9mm and 40 S&W. TG is a very fast powder that burns hot and has a tendency to get "squirrelly" (technical term) when loaded to the upper end of the scale in these high pressure rounds.

    The window from "start" to "max" is very small with TG. Take the 9mm 125gr bullet for example. Hodgdon lists a "start" charge of 4.1gr and a "Max" charge of 4.4gr. That's a measly .3gr from start to max. Not enough wiggle room in my book.

    Most powder dispensers are at best accurate to +/- .1 grain. With this in mind, a desired charge of 4.2gr of TG can yield ammo from Min to Max all in the same ammo box. Couple this with the fact that TG does not play nice when pushed hard and you have a potential problem before you even start.

    Not only that a double charge of TG in a 9mm case will be very difficult to spot. That would certainly ruin your day.

    Do the Google on TG and KB's in the 40. You may find that it was the powder used in the majority of KB's.
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