Checking Volume of Case

Discussion in 'Reloading' started by bigdumboy, May 25, 2015.

  1. bigdumboy

    bigdumboy Well-Known Member

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    Have a .264 win mag starting to load for want to check volume on brass I am going to use. Used a little hot glue to stop up the flash hole. Checked weight of case and zero scale add water till a dome formed on top of case checked weight again if my thinking is right that should give me the powder volume of case is that right?

    Thanks Dirk
     
  2. davkrat

    davkrat Well-Known Member

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    That will give you the H2O capacity. The powder volume will be slightly less due to the bullet protruding in to the case. Powder densities (ball vs stick) will further change how many grains will fit but the H2O capacity will give you a measure to compare your chamber and brass choice to another's chamber.
     
  3. bigdumboy

    bigdumboy Well-Known Member

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    The reason I asked on my quickload .264case has water volume of 82 when I measure the case I am using it came up 85.6 the brass is nosler does that mean all brass will be different
     
  4. ShtrRdy

    ShtrRdy Well-Known Member

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    Yes, different brands of brass, (and sometimes different lots of the same brand), can have a different H20 capacity.
     
  5. davkrat

    davkrat Well-Known Member

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    Different brands of brass will have different thickness and therefore internal volume. That's why you should never take a max charge load developed in one brand of brass and simply interchange to another. If you went from a fairly thin brass with lots of internall volume to a brand with thicker brass you could quickly be over pressure in what you otherwise consider a safe load. Also your accuracy nodes will not likely be the same.

    I have never used Quickload so I don't have any experience playing with the case parameters. As with any load data it is just a reference point. Only careful trial and error will safely tell you limits of YOUR chamber, brass, primer, bullet and powder combination. I also believe it is better to run the H2O capacity test with unsized fired brass. The dead primer will plug up the primer hole and the expanded case will be a better representation of your brass and chamber's capacity. If you find your max pressure signs show up a grain or two higher than the Quickload estimate I would assume it's because you have slightly more internal volume than the program calculated from.
     
  6. bigdumboy

    bigdumboy Well-Known Member

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    Thanks for taking the time to read my posts and respond the brass was new so I will do the same test after I fire it thanks for you help and insight.

    Dirk
     
  7. g0rd0

    g0rd0 Well-Known Member

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    according to Homer Prowley this is what you do
    get 10 brass fired from your rifle (same brand)

    deprime, neck size and clean them

    lube the inside of the neck and place your bullet of choice in the mouth of the brass and chamber it (the bullet will seat against the rifling).

    now weigh 1 then using a hypo needle (you can get these easly from a farm supply store), fill with water through the flash hole. Using a qtip dry out the primer pocket. Weigh it again subtract the empty from the full, do the other 9 add the 10 CC's devide by 10 and that will give your CC


    For different weight, manufactures and styles of bullets the case capacity will change
     
  8. Wyo7200

    Wyo7200 Well-Known Member

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    You want to take a piece of paper towel and suck up that meniscus to get it as level to the case as possible. QL calculates the usable case capacity by taking the COAL of the cartridge, the OAL of the bullet, and your measure of case volume in H2o. It figures how much of the bullet is in the case, and displaces that amount of bullet volume from the H2o volume to determine the Useable Case Capacity.

    For QL purposes (and no disrespect to the info provided) g0rd0's method (which is really jumping to Useable Case capacity) will underestimate the volume that you need to enter QL. You will have to seat the bullet to your desired OAL (matching what you entered into QL), measure as stated by Homer, and then adjust the Maximum Case Capacity overflow input to match the Useable Case capacity output.

    Since each method involves entering in a volume into QL, let QL calculate the useable case capacity as it is designed to do. Good idea to take the time to measure your bullet's OAL at this time as well.

    QL has measured propellant density for each powder in its database, enabling it to calculate the fill % and other estimates.
     
  9. J E Custom

    J E Custom Well-Known Member

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    +1
    The way I like to measure H2O volume is with fired brass with the spent primer still in and as fired.
    this give you the usable volume of your chamber and brass. To be more accurate with water volumes
    after filling the case up to the top of the neck, I take q-tips and wick the water out of the neck until it is even with the bottom of the neck (No water in the neck) with it setting on the scale. this is a more accurate way of telling what your case will hold with a bullet seated above the powder.

    Then I find the powder best suited for what I want to achieve and using a drop tube (To get the most weight of this powder possible in the case up to the neck) so I know what the maximum I
    can use. I can always drop the/a charge directly into the case, but if I need to up the charge a little , the use of a drop tube is an option.

    As stated , different powders, chambers and brass will vary the results but at least give you a usable measurement. (Not just the biggest that is not practical).

    J E CUSTOM
     
  10. DocB

    DocB Well-Known Member

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    Taggin in fellas. Thanks :)

    DocB
     
  11. Mikecr

    Mikecr Well-Known Member

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    No, Wyo7200 is right.
    Don't try anything fancy. Just focus on full case H20 capacity & let QL do the rest.

    -The case does need to be fully fireformed & unsized & trimmed to the same length
    -Add a few drops of alcohol to the water to reduce it's shear and get better fill
    -Fill the case from mouths with an eye dropper
    -A tissue corner works best for leveling meniscus(watch this close from the side)

    Now if you FL size those cases & measure H20 capacity again, you'll see it all fall apart..
    So if you FL size, don't even bother trying to match cases by capacity.