Powder thrower accuracy?

Discussion in 'Reloading' started by bookworm, Sep 5, 2009.

  1. bookworm

    bookworm Well-Known Member

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    I have an older (probably 30 years old) RCBS "Uniflow II" powder measurer.

    I have two questions:

    1) What type of repeatability should I be getting out of this unit with an extruded type powder (H1000)?

    2) How much load accuracy/precision should I be aiming for when developing long range hunting type loads for a .300 win mag?

    I was playing with it today and it seems to be throwing +/- 0.4 gr which seems like a lot to this novice.
     
  2. britz

    britz Well-Known Member

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    Don't waste your time worrying about how accurate your thrower is... you should be weighing each load anyway. 0.1 Grain accuracy is what the norm is. It takes a pretty good thrower and only a certain few powders will meter really well. Small round ball or super short cut will yield the best results.
     

  3. winmagman

    winmagman Well-Known Member

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    I agree with britz, I weigh each load. I set the thrower a little lite and use a powder trickler to bring the charge up to my desired weight.

    Chris
     
  4. bookworm

    bookworm Well-Known Member

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    Thanks fellas.

    This is the process I've been using, but wondered if that was normal. It's slow, but I guess the only option short of spending several hundred on a an electronic meter/scale.
     
  5. milanuk

    milanuk Well-Known Member

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    I was going to say I'd expect +/- 0.2gr at the best with that kind of powder, possibly up to +/- 0.5gr. Sounds like thats about where you're at.

    For short range hunting ammunition in a big cartridge, you might get away with it. Some load development models work you towards 'nodes' where the load is more tolerant of such deviations. Even so, considering that loads used for long-range anything tend to be closer to 'max' than 'min', and part of the goal is reducing variables... weighing charges tends to be party of the bargain.
     
  6. bigbuck

    bigbuck Well-Known Member

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    I use an old rcbs powder thrower also. I load for a 300 rum and I use h-1000 and retumbo powders . I can say without a doubt the best way to use this setup is with a rcbs or other powder trickler I do not EVER rely on just dump and go set as close to your scale as possible once your almost their tricle in the rest this is the most accurate way for this setup after all that's why we reload:)

    BIGBUCK