Compressed Loads Are Bad Juju!

This is a discussion on Compressed Loads Are Bad Juju! within the Cartridges & Calibers forums, part of the Sniping Related category; As handloaders we strive for consistency. We try very hard to have each and every round just like the round before it and as close ...

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  1. #1
    Senior Member oneshotonemiss's Avatar
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    Compressed Loads Are Bad Juju!

    As handloaders we strive for consistency. We try very hard to have each and every round just like the round before it and as close to perfection as we can achieve.

    So much for the obvious.

    Every powder no matter what shape it is is coated with chemicals that effect the burn rate.

    Compressed loads cause individual particles to break. Some types such as extruded will break more readily than say a flake powder. The breaks expose non-coated surfaces and makes them burn differently (usually faster) than intact ones. The particles are also pushed together more tightly.

    Under compression, this breakage and compaction cannot be predicted, controlled or consistent. It is chaotic.

    Burning powder under such circumstances cannot be the same from round to round as there is no way to control the compression and breakage.

    This is the very definition of inconsistency and should be avoided.
    "A question that sometimes drives me hazy: am I or are the others crazy?"
    Albert Einstein

  2. #2
    Senior Member Longshot38's Avatar
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    I'm sorry but I have to disagree on the basis on running compressed and get just as good or better consistency out of the load. I found my 300 wby shoot exceedingly well with compressed loads.

    Also Federal did a study at one time on compressed loads and found that the burn rate was more consistent with compressed loads vs non compressed. They also showed that they got consistently lower pressure running compressed. Now this study was not published to my knowledge but it is what was passed down the line to me.

    I'm not saying that compressed is the only way to load but what I am saying that it is a technique that should not be discredited. Depending on what you loading for you may do better running compressed.
    Recognize what is in your sight, and that which is hidden from you will become plain to you.

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  3. #3
    Senior Member SpaceGoD's Avatar
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    The best consistency out of 3 AR's I've loaded for have been compressed loads.

    Isn't there a theory that underfilled cases are inconsistent because there isn't a consistent powder column behind the bullet when it's turned horizontal?
    Walther P99 9mm/AAC Evo
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  4. #4
    Senior Member Longshot38's Avatar
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    SpaceGoD you are correct. Underfilled cases don't burn as consistently as compressed loads due to powder column. Remember to little pressure can be just as dangerous as to much. From all the research I've done most powders burn best loaded anywhere from 90% to slightly compressed. Of course figuring out what works best for your rifle is the point of handloads.
    Recognize what is in your sight, and that which is hidden from you will become plain to you.

    Sum dominus fati: sed sum princeps meae.

  5. #5
    Senior Member shane4639's Avatar
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    I don't like to run compressed loads if I can avoid it, simply because I don't get a warm and fuzzy when I hear crunch. I try to keep my load density as close to 100 percent as possible but without the crunch sound.

    I have often thought like oneshotonemiss on this. The example comes to mind when I think about it is a "whistling pete" firework. When you light it, it will spark and make a loud whistling sound. If you compress the tube in a vise, and then light it, it just goes bang. I have wondered what it does for pressure. Then I apply the same thinking to a compressed load. It may not be an accurate model, but its the one in my head when I hear that crunching sound.

    If I get to the point that I hear the crunching sound in my load development, I just find another powder that gives me the load density and burn rate I want, without the crunching sound. I can't say its bad to crunch, but its not my preferred method.

    I have never tried to turn my 308 into a 300WM. I have both, if I need a bigger golf club I get one. I don't try to push the performance on one past its intended envelope. I have read that compressed loads can be very accurate. I have used them and not had any problems, but they just don't give me a warm fuzzy.
    What's in a name? That which we call a rose, by any other name would smell as sweet.
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  6. #6
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    How much compression, do you pack 50% more or 5% more. Lets say that some bits break and create new surface is it really more problematic than 80% load which has plenty of air left and powder settles on the bottom of a case - how do you predict burn with powder that has generous amount of space left for movement - does it stay in the back, does it run towards bullet, did i shake or did i stirr?

    I'd say based on my reading on powder/loading articles that variations in powder charge are not so critical so if you stay within reasonable amount of variation you are gtg.

  7. #7
    Senior Member shane4639's Avatar
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    Quote Originally Posted by sharac
    How much compression, do you pack 50% more or 5% more. Lets say that some bits break and create new surface is it really more problematic than 80% load which has plenty of air left and powder settles on the bottom of a case - how do you predict burn with powder that has generous amount of space left for movement - does it stay in the back, does it run towards bullet, did i shake or did i stirr?

    I'd say based on my reading on powder/loading articles that variations in powder charge are not so critical so if you stay within reasonable amount of variation you are gtg.
    I wouldn't use a powder that offered 80% density any more than I would use one that was at 120%. I try to get as close to 100% as I can without hearing crunch, as to which is worse one underfilled by 20% or over filled by 20%, I wouldn't do either, but if I had to choose it would be the lighter of the two. I agree that so long as you are reasonable, there is no problem with compressed loads, I only stated I avoid them because I don't give me a warm fuzzy.
    What's in a name? That which we call a rose, by any other name would smell as sweet.
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  8. #8
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    I agree crunching, hitting and all other "violent" sounds and gun powder or explosives usually don't mix well.

    I was more reffering to original post as 105 compression isn't that bad i think worse than crunch is neck tension and COAL increase over time of compressed loads.

    I think all strive to get 100% case filling with tightest grouping possible while achieving maximum speed with optimum barrel time and minimum barrel wear but i'm afraid noone is quite there yet (and so it should be since that is one of the beauties of reloading).

  9. #9
    Senior Member shane4639's Avatar
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    Quote Originally Posted by sharac
    I agree crunching, hitting and all other "violent" sounds and gun powder or explosives usually don't mix well.

    I was more reffering to original post as 105 compression isn't that bad i think worse than crunch is neck tension and COAL increase over time of compressed loads.

    I think all strive to get 100% case filling with tightest grouping possible while achieving maximum speed with optimum barrel time and minimum barrel wear but i'm afraid noone is quite there yet (and so it should be since that is one of the beauties of reloading).
    I think you are generally going to find best accuracy potential with a powder density somewhere between 95-105%. When I was younger and wanted speed, I crunched on a regular basis. Most of my current loads are probably somewhat compressed, they just don't go crunch, but you can't really shake the powder in them either.

    I am sure people with more experience than I, use loads that go crunch on a regular basis. I wonder how much better a load of 104%, shots than one of 96%. Is the difference really worth the effort? For me now if I hear a crunch, the answer is "no". For someone else it could be "yes". Just like anything else involving reloading, you have to use your head.

    You are I are really on the same sheet of music. I have used compressed loads in the past and had no issues. I don't use as much simply because I have wondered what happens to the burn rate when compressed and I don't feel the need for speed anymore. I guess I am just getting old. I have done a little research on it to try to give myself a warm and fuzzy about it. I have found nothing that would indicate they are unsafe.
    What's in a name? That which we call a rose, by any other name would smell as sweet.
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  10. #10
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    I guess I am just getting old.
    Aint we all and on the daily basis .

    I think moderation is a keyword here and unless doing some testing and experimentation (i.e. willing to risk rifle, willing to risk limb or three ) staying within safety zone equals long life in one piece. Going to the limits while doable and with some common sense also relatively safe has potential to become standard practice add to this years of such practice and probability that something will go wrong eventually increases. We men are beasts of habits and i'd rather be used to playing it safe and sometimes do the "wild" thing then vice versa.

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