Case % fill ?

Discussion in 'Reloading' started by ol mike, Jun 14, 2007.

  1. ol mike

    ol mike Well-Known Member

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    Do you guys consider how full the case is when choosing a powder ?

    I remember Kirby talking about pointing a gun down so the powder was laying against the bullet -a void between the primer and powder and there being a big change in ES.

    I loaded up some 75gr v-max in a 25-06 w/varget and there is about -guessing 75% case fill.
    I shot another coyote the other day at a very steep downhill angle and the just wondered later if anyone considers case fill percentage when picking a powder.

    Also want to say thanks to Remingtonman-25-06 for the H-4831 tip -my factory 25-06 shot a .723" and .824" at 218yds.-I couldn't believe it!!85gr nos bt /58gr h-4831 /cci lrp /rem case...< My new coyote load !

    Also does the h-4831sc use the same charge weight as the standard h-4831 ?
    I'm thinking a load would need backed off a little.
    Well thanks for any help.-Mike
     
  2. jwp475

    jwp475 Well-Known Member

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    Yes I do consider the load density when chooseing a powder.I like to be close to 100% load density if poissiable. H4831 and H4831SC uses the same load data per Hogdon,but consider a change between the two the same as changeing lots of the same powder..........
     

  3. Gustavo

    Gustavo Writers Guild

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    I always look for the slowest possible powder, which by definition will fill the case as full as possible too.
     
  4. LRHWAL

    LRHWAL Well-Known Member

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    Not to highjack this, but whilst we are at it... we have limited (very!!) choice in SA. Any thoughts on fillers like maize meal or cream of wheat, or whatever?
     
  5. 7mmAI

    7mmAI Active Member

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    When is a case considered 100% full? Is it full to the base of the neck? or is it full when you consider the aprox. amount of space that the bullet base will take up when seated and then powder up to the neck?
    I am working up a load for my 280 improved and it looks like 61 gr of H-4831sc with the 160 accubond must be at 100% without to much compression. Thanks Dean
     
  6. CatShooter

    CatShooter Well-Known Member

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    [ QUOTE ]
    When is a case considered 100% full?... < >... or is it full when you consider the aprox. amount of space that the bullet base will take up when seated and then powder up to the neck? Thanks Dean

    [/ QUOTE ]

    Yes.

    Is considered full when the level of settled powder comes up to the base of the seated bullet - id est, 100%.

    Compressed charges are rated in the amount over that amount.
    So if 50 grains fills the case to the base of a 170 grain "X" bullet, then 55 grains is a 110% compressed load.

    .
     
  7. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    Ol' Mike,

    It greatly depends on what chambering you are talking about, what bullet weights are used and what powder types you are using.

    First off, The larger the chambering or should I say the larger the case capacity of a certian chambering, the more important load density seems to be as far as consistancy goes on average at least.

    Also, if your using an easy to ignite stick powder, running lower end load densities generally will not cause huge velocity spreads.

    If your using a large amount of ball powders which are harder to ignite, you will see more velocity spreads.

    Lighter bullets also tend to be effected more by low load density as far as velocity spreads but again, this depends on the powders you are using.

    Its good rule of thumb to look for at least 80% load density if your using stick powders and I like at least 90% for ball powders at minimum.

    With the powder charge weight your using and the type of powder your using, I suspect you will not see a dramatic velocity spread.

    Now if you were shooting a 275 STW with a 75% load density, you would see a much larger effect.

    As far as H-4831SC, I would back off 5% and work up your load again, it seems to be a very bit faster burning then standard H-4831. I am sure simply because of the larger surface area of the smaller pieces of powder is the reason.

    Kirby Allen(50)
     
  8. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    LRHWAL,

    YOu can use fillers and I have played with them a bit in some of my really large AM wildcats with reduced loads just for testing sake. I would not use corn meal or anything similiar. The reason is because they are combustable and will increase chamber pressures. I would have never thought this until I tried it.

    Dycron filler works very well. Same stuff they use as buffer on magnum shotgun shells. It is not combustable and is very light for volume as well.

    Still, its best to just use a proper burn rate powder to get 80 to 90% load density in my opinion.

    Kirby Allen(50)