Powder scale accuracy

Discussion in 'The Ammo & Reloading Forum' started by stev32k, Oct 24, 2012.

  1. stev32k

    stev32k Well-Known Member

    Oct 19, 2012
    Mobile, AL
    I'm trying pick a recipe for 9mm and .40 S&W. Most of the powder weights listed the Lyman manual (for 9mm) range from about 3gr to about 7gr. The difference between the starting weight and the maximum weight is on the order of 0.5gr to about 1.5gr(some a little more and some a little less). Converting to grams the between the starting and max weights is .03 grams to .09 grams.

    The problem I have is the triple beam balance I own is accurate to 0.1 grams. I checked the scale error and repeatability with certified calibration weights and it's pretty good with a weight change of 0.1 gram, but any less is just estimation.

    So, do I need a new balance? If so any recommendations?
  2. stev32k

    stev32k Well-Known Member

    Oct 19, 2012
    Mobile, AL
    Since posting the first time it occurred to me that maybe the solution would be to set the powder charge using 10 cases instead of just one. That would work like this: weigh 10 empty cases with primers then fill all 10 with powder and re-weigh, subtract the empty weight, record the total powder weight and divide by 10. Then make adjustments as required and repeat.

    Would that work?

  3. medalguy

    medalguy Member

    Feb 20, 2009
    New Mexico
    That's what I do. I use a beam balance to measure out powder charges when doing a ladder test. Once I determine the charge, I set my Dillon measure to what I want, run 10 loads, do this three times and average the thrown charges. This way I'm right on the money with the powder measure.

    But I throw the charges into the pan to weigh them. Throwing charges into primed cases might not work because sometimes a grain of powder can stick in the flash hole, throwing your estimates off.
    Last edited: Oct 24, 2012
  4. gdmoody

    gdmoody Moderator Supporting Member

    Sep 7, 2007
    Athens, Georgia
    I don't understand why you need to convert any thing to grams. If your scale does not weigh in grains, throw it out and buy yourself a new one.
  5. woolleyworm

    woolleyworm Well-Known Member

    Feb 23, 2009
    SW Fort Worth
    yes, you need a new scale. I always advise a scale specifically for reloading. you do not want conversions to get thrown in the mix and cause an error.
  6. stev32k

    stev32k Well-Known Member

    Oct 19, 2012
    Mobile, AL
    Do you have any recommendations for a scale?
  7. bustedmp

    bustedmp New Member

    Jul 3, 2012
    Shamokin PA.
    Any good scale, Lyman, Lee, Rcbs, any dedicated reloading scale. I have a Lee scale because it came with my first reloading kit, and I really like it. It has been a good little scale for me. I use my scale to get my measure set where I want it, and check every
    5th charge on the scale.
  8. woolleyworm

    woolleyworm Well-Known Member

    Feb 23, 2009
    SW Fort Worth
    It mainly depends on what you want to weigh. If it's just charges, then an RCBS 505 is my choice for smaller beam scales. If you want to weight heavier stuff, then the best balance beam in a reasonable price range is the RCBS 10-10, best all around scale IMO. I mainly use the Rangemaster 750 electronic and have a 505 for back-up. I've also used the Lyman scales and they are very good also. I have used the Lee scales and I didn't care for them, they didn't operate as "smoothly" as others.
    If money is no object and you want the Caddy-Lac of scales, Ohaus makes the Dial-O-Grain. I've used one and they can handle any measurement you need for reloading, but they're hard to find and usually $250+.

    btw- Ohaus makes all of the RCBS and Lyman scales, they're just rebranded and reloading specific.(grains only, no grams)
    Last edited: Oct 24, 2012
  9. stev32k

    stev32k Well-Known Member

    Oct 19, 2012
    Mobile, AL
    I have the Ohaus triple beam balance. It has the same capacity and readability as the Dial-O-Gram ie 0.1 gram. Is there another Dial-O-Gram that has better readability?
  10. LDBennett

    LDBennett Well-Known Member

    Dec 20, 2003
    Hesperia, CA
    I have the RCBS 304 which appears to be the Ohaus Dial-O-Grain (??). Once I bought my Dillon digital scale some 15+ years ago I have NEVER used the RCBS beam scale. It is an unused backup.

    Personally, I dislike beam scales. They hunt for the answer, swing back and forth. I've had several and they are all the same. They may be intrinsically more accurate (if you can every get them to stop swinging) but not nearly as handy. To verify my Dillon I have a Lyman weight set. I find the accuracy of the Dillion digital excellent. I have plotted the error over the range I use and it is very small indeed and I don't bother to compensate for it.

    There is a fallacy in the reloading process some fall pray to: Weighing every charge and getting every load right on the money. The latest expert thinking (not me!!!) is that for rifle loads getting the load to with in a few tenths of a grain is more than accurate enough as all the other accuracy impactors make that small of an error in powder charges minuscule in its effect on accuracy. For pistol charges, a tenth grain accuracy is easy to obtain and is good enough.

    I prefer to use W231 (same powder as HP38 in a different can with a different label according to Hornady who sells both) rather than Bullseye or some of the other really fast pistol powders because it takes a bit more making any errors in charge weight less important.

  11. Alpo

    Alpo Well-Known Member

    Feb 3, 2007
    NW Florida
    1 gram is 1/28 of an ounce. Therefore 0.1 gram is 1/280 of an ounce.

    When 1 grain is 1/437.5 of an ounce, it appears that 0.1 gram is 1.5 grains.

    If I am loading 380, with a charge of 3.0, and my scale's "accuracy" is so sloppy that it allows 4.5 grains to read as 3.0, so I am loading a 50% overload, this is a BAD THING.

    Or, to look at it another way, the accuracy on ANY reloading scale out there is going to be NO MORE THAN 0.1 GRAIN. Not 0.1 gram, 0.1 grain.

    0.1 grain is 0.00648 grams.

    You triple-beam is nowhere near precise enough to work as a powder scale. It would be like trying to do laboratory work with a bathroom scale.
  12. soundguy

    soundguy Well-Known Member

    May 8, 2012
    mega ditto...
  13. soundguy

    soundguy Well-Known Member

    May 8, 2012
    i was wondering about that. Both my sacles are .1grain accuracy. a .1gram accruacy scale just ain't gonna cut it.

    even the cheap lee scale is better than that

  14. stev32k

    stev32k Well-Known Member

    Oct 19, 2012
    Mobile, AL
  15. deadin

    deadin Well-Known Member

    May 16, 2006
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