1. Attention: We have put together a thread with tips and a tutorial video to help with using the new software. Please take a moment to check out the thread here: Trapshooters.com Tutorial & Help Video.
    Dismiss Notice

Powder weight or volume?

Discussion in 'Shooting Related Threads' started by Wthomas, Apr 30, 2010.

Thread Status:
Not open for further replies.
  1. Wthomas

    Wthomas Member

    Joined:
    Jun 9, 2008
    Messages:
    72
    What is more critical in powder measure, the weight or the volume. With my loader in the garage and subject to 20-30 degree temperature swings from say evening to midday, I am seeing as much as a full grain or more diference between powder drops with the same bushing. I make sure to calibrate my scale before each loading session and check several powder drops before starting. I have generally changed the bushing to get the weight back to recipe ranges, but at times doing this has left me with loads that are either heavy or light. So what is the correct measure, weight or volume. Weights are consistent during a session, so it is not mechanical with the press, hopper full/low also does not change the dropped weight. Powder is Clays or Clay Dot.

    Bill Thomas
     
  2. goatskin

    goatskin TS Member

    Joined:
    Jun 24, 2009
    Messages:
    1,781
    At the end of the day, it probably doesn't matter much, but consistent weight is what you're after.

    If you keep your powder in your house, weight swings for the same bushing will be smaller.

    Both temperature and humidity affect the volume dropped to fill the thimble, which, of course affects the weight.


    Bob
     
  3. short shucker

    short shucker TS Member

    Joined:
    Jan 29, 1998
    Messages:
    3,938
    Smokeless by weight and Black by volume, always!

    ss
     
  4. BigM-Perazzi

    BigM-Perazzi Well-Known Member

    Joined:
    Jan 29, 1998
    Messages:
    8,542
    Location:
    HELL, MICHIGAN
    ALWAYS by weight. Never by volume, except blackpowder.
     
  5. BDodd

    BDodd TS Member

    Joined:
    Jan 29, 1998
    Messages:
    3,594
    Those swings are excessive - I'd be worried about why that happens although the first one or two are bound to weigh a little heavy, perhaps a 1/2 or 3/4 of a grain if your powder has settled for a few days in your powder bottle. I recommend weighing the actual drop you will use in at least the first and second shells and simply remove a few flakes if they are heavy. Once you're getting uniform drops then decide on a, probably permanent, bushing change if necessary....breakemall.....Bob Dodd
     
  6. skeeljc

    skeeljc Supporting Vendor Supporting Vendor

    Joined:
    Aug 27, 2007
    Messages:
    3,779
    Location:
    Terre Haute Indiana
    First, the only accurate way to weih the powder charge is to weigh the powder dropped during actual loading. This means remove the shell just before the powder is dropped and put it on a digital scale and zero the tare. Then put the shell back in the loader, cycle the loader to drop the powder and remove the shell and weigh it. This is the most accurate way to check the powder drop. An alternative is to use a device to catch the powder so it can be removed and weighed. P/W sells a Shot & Powder Measure Kit that will do this.

    Once you have established a load then use the same bushing to reproduce the load. The only time I re-check the powder weight is when I open a new 8 pound container of powder. Powder should be weighed at 70 degrees and 50% relative humidity.

    If you do not want to go to all the trouble just use a reliable source (like Hodgdon's website) and trust their data.

    Jim Skeel
     
  7. The Rock

    The Rock Active Member

    Joined:
    Jan 29, 1998
    Messages:
    1,492
    The thing is this, weight is what you want but all loaders use volume to get the weight desired. The same volume with the same batch of powder will give you the same weight.

    In other words the correct volume will be the correct weight. They go together.

    When you weight your powder you are weighing the volume of the bushing you are using.

    Rock

    Jim
     
  8. phirel

    phirel TS Member

    Joined:
    Jan 29, 1998
    Messages:
    9,556
    Bill- I do not understand what is happing with your powder drops. Some things do get denser as the temperature decreases. Other things (water) gets heavier as the temperature decreases than at a point, they get lighter as the temperature goes down more. But powder does none of this. The powder bushings will not change enough with temperature changes to account for what you are experiencing. I remain confused over your observations.

    Pat Ireland
     
  9. Wthomas

    Wthomas Member

    Joined:
    Jun 9, 2008
    Messages:
    72
    Thanks for the input guys. I think I will continue to trust the scale and adjust my bushing to throw the weight I need. On my P/W 900, that is varying from a J1 too a Pacific 447 to a P/W K for 18.2 grains. That is takeing the powder directly from the drop tube, after dropping at least 2 batches. From then on the load is consistent with the installed bushing.

    Again, Thanks for the thoughts.

    Bill
     
Thread Status:
Not open for further replies.