3. Chargemaster Accuracy

Chargemaster Accuracy


  • So...I had someone call into question the accuracy of the chargemaster a few weeks ago. It has been mulling over in my mind ever since. I like the speed and ease of use of the chargemaster but if it is the reason I get flyers once in a while I will do something else. I do not want to spend the money on a promethus right now...I have too many other things I would rather have...so depending on what I decide I might let the chargemaster throw the weight and then trickle on the satorius lab scale.

    For the test I used the same powder and charge I always use. I told the chargemaster to throw 44.5 grains of varget. Varget weights about .015 gr per granule meaning that my satorius at 0.02 gr resolution can almost see every granule. However the chargemaster scale is at 0.1gr resolution and guaranteed to be within + or - 0.1 grain. That can be a full 0.1 grain high and 0.1 grain low and read the same thing and still be in spec.

    Anyways...here are the first 20 that I weighed for the test. I let the chargemaster throw the charge. Then if it still read 44.5 on the chargemaster scale I would count it and weigh it on the satorius. If it was over or under on the chargemaster scale I threw it back in the tube and didn't count it. In other words the chargemaster scale settled on "44.5" for every one of these charges.

    1. 44.60
    2. 44.56
    3. 44.54
    4. 44.56
    5. 44.56
    6. 44.48
    7. 44.52
    8. 44.52
    9. 44.62
    10. 44.52
    11. 44.44
    12. 44.52
    13. 44.50
    14. 44.52
    15. 44.52
    16. 44.56
    17. 44.60
    18. 44.56
    19. 44.58
    20. 44.48

    On this first run the high was 44.62 and the low was 44.48. That is an extreme spread of 0.140 grains...which is within tolerance for the scale (remember + or - 0.1 grains = an E.S. of .2 grains. Average for this run of 20 is 44.538 grains

    On the second run I decided that I would wait for the chargemaster to read 44.5, then I would lift the pan and set it down again. If it still read 44.5 I would weigh it on the satorius. This culled out 2/20 (10%) that were high the second time and dead on before I lifted and set the pan down again, but didn't seem to make a difference overall

    1. 44.60
    2. 44.56
    3. 44.58
    4. 44.48
      1. 50
      1. 52
    7. 44.50
    8. 44.44
    9. 44.44
    10. 44.38
    11. 44.50
    12. 44.52
    13. 44.42
    14. 44.46
    15. 44.48
    16. 44.50
    17. 44.54
    18. 44.56
    19. 44.56
    20. 44.52

    On the second run the high was 44.60 and the low was 44.38. That is an extreme spread of 0.220 grains...which is slightly outside the tolerance for the scale (remember + or - 0.1 grains = an E.S. of .2 grains). Average for this run of 20 is 44.503 grains. While the average is closer...the spread is a problem.

    Now...The long term numbers is what really reveals the accuracy of a scale. consider the numbers over the course of these 40 rounds instead of 20. E.S. is 0.24 grains and average is 44.5205 grains. The average is great...but when you consider that you have a loaded round that is 0.14 below average (44.38) and another round that is 0.1 above average (44.62) I think you are going to have fliers due to powder weight being that different. I guess what I can do is to let the chargemaster do its thing and then weigh every charge on the satorius before dumping it into a case. That way I can throw out the extremes and I still won't have to trickle.

    I can throw back 25% of the charges (the 10 extreme ones) and get the ES down to 0.1gr and the average would then be at 44.51. It would give me a low charge of 44.48 and a high charge of 44.58.

    I can throw back 16 of the 40 (40%) and the es is down to 0.06 grains with an average of still at 44.51 grains. to me that would be tolerable...although 0.06 grains might still give me fliers they are probably within the realm of my abilities. I guess I need to weigh them twice...set parameters and throw back anything that is outside those parameters.

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  • Great write up. I did a similar test on chargemasters years ago, and came up with similar results.

    If you are in the center of a solid node, +/- .1gr isn't going to cause a flyer. However, if you're on the edge of it... it certainly can. This is more true with small cartridges like a .223 than larger cartridges. The higher the charge weight, the smaller the significance.

    Flyers almost always come from seating pressure variation and other brass inconsistencies. When seating bullets, be sure to cull the rounds into three groups. Those that seat soft, those that seat "normal" for your average pressure, and those that seat hard. This identifies inconsistencies in the brass neck better than any other known method. Whether by "feel" or by a force indicator gauge such as the hydraulic arbor seaters... that pressure difference tells all.

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  • Makes sense. I just ordered a 21st century hydraulic press a few days ago. I like my K&M but all I have to go on there is feel. I thought the hydraulic was a good design. I guess we will see.

    Once the corn is out I might try to work up the load again. There are a lot of things in your write up that I didn't think of the first time that will probably yield better results. However I am down to about 150 rounds of smk's left...so I might switch to bergers before I do the load development again. I will probably order 100 each of three different bergers just to make sure I get one that will shoot well in my rifle.

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  • What model Sartorious are you using?
    Orkan mentioned some scale in the $250-$300 range that was a decent compromise on SF. Tree 2 something.
    I don't think it was an expensive Force Restoration Scale.

    Your results have me thinking that a quality thrower like a Redding BR30 for 5.56 or the Match 3 BR for 30-06 and a good digital scale would be just as fast as throwing half of the charges back in the hopper.
    I could get into it one piece at a time. I picked up a Ohaus made RCBS 510 already.
    Precision had the Redding 3BR Match on sale for $139.
    Let me check if it still is.

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  • @hypo

    Acculab vic123 is the scale I have. It was replaced by the satorius 123 but is essentially the same scale.

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  • @hypo said:

    What model Sartorious are you using?
    Orkan mentioned some scale in the $250-$300 range that was a decent compromise on SF. Tree 2 something.
    I don't think it was an expensive Force Restoration Scale.

    Your results have me thinking that a quality thrower like a Redding BR30 for 5.56 or the Match 3 BR for 30-06 and a good digital scale would be just as fast as throwing half of the charges back in the hopper.
    I could get into it one piece at a time. I picked up a Ohaus made RCBS 510 already.
    Precision had the Redding 3BR Match on sale for $139.
    Let me check if it still is.

    Nevada Weighing Tree HRB203 is the one I've got.

    Throwing under with a powder thrower would indeed be a lot faster than trickling low with a chargemaster.

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  • Thanks.
    I wonder how close a decent charge thrower can hold?
    Can a good one beat the ES of the ChargeMaster?
    Type of powder would be a big factor and a well practiced technique.

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  • Most can hold within a tenth or two, depending on powder. It's all in your technique in how you run them. Throw slow, different charge than if you throw fast. It requires a LOT of technique to get them to be real accurate.

    The uniflow on my prometheus has been modified to be really good, and I can get within a tenth usually. Pretty amazing actually. I still prefer weighed charges as opposed to charges based only on volume. ... but throwing light and trickling up is a very good method, as indicated by the Prometheus design. ;)

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  • https://www.precisionreloading.com/cart.php#!l=RE&i=03500

    Redding Match 3 BR and the Weighing Tree, could it compete with the Chargemaster?

    Would upgrade scales later.
    I may order the thrower tonight while it is on sale.
    Comfort shopping. When I have to spend money on stupid stuff that other people cause, I have to spend money on myself to balance things out. Arrgh. $1k brake job!!!!!!! I could have really gotten set up to reload for that much.

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  • http://www.scout.com/military/snipers-hide/forums/5532-reloading/14885938-redding-3br-powder-measure-throwing-not-so-accurate-charges

    I don't thin ANY powder thrower is going to be as accurate as a chargemaster. The purpose of the thrower would be to throw low, and then trickle up with a precise scale. For that, a cheap thrower will suffice. No need for micrometer adjustment and spending a lot of money. That money would be better spent on a more accurate scale.

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  • Thanks. I'll be looking at scales next.

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  • For throwing light to trickle up, the Lee powder thrower does really well for $30. It handles stick powder very well too.

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  • yeah...I really don't want to trickle. I've done that. I will probably check my node with the satorius and make sure that I am in the middle of the node. Then I will try and see how it shoots. If it still has fliers I can double check and throw back powder...but I don't want to trickle.

    When I say flier...I am talking about a bullet that WIDENS the group to 3/8" or so. This thing is well under 1/2" and has had many single hole groups. I am just trying to figure out why the hole is sometimes oblong instead of round.

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