Charge master accuracy

Discussion in 'Reloading Forum (All Calibers)' started by dthomas, Jan 5, 2020.

  1. rsmithsr50

    rsmithsr50

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    it is more than good enough for the large targets in f class.
     
  2. bichettereds

    bichettereds Gold $$ Contributor

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    Nothing I said in my post was BS. I stated that a Chargemaster (did not say out of the box) should be capable of +/- 0.05 (.1 ES) and I clearly stated that I made a couple simple modifications, which did not cost a penny and anyone can do. Whether the potential buyer chooses to verify it with a more expensive scale is up to them. I think the information I provided is helpful to any potential buyers.

    Pretty simple english there.
     
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  3. rsmithsr50

    rsmithsr50

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    NO THIS IS WHAT YOU SAID
    "last time I checked mine, throwing the complete charge with my chargemaster and verifying with a gem pro 250, I had an extreme spread of 0.12grs with most falling inside 0.06grs."

     
  4. rox

    rox

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    I had similar results when I was testing a CM with a FX-120i back in 2012/2013. 90% were within +/- 0.05 and 100% within +/-0.07. The CM had a drinking straw and everything was warmed-up for at least 24 hours in a fairly temperature-stable environment, anti-static precautions etc.

    I was actually looking at whether CM accuracy and speed could be improved be 'pre-charging' with a thrown charge, and just using the CM to trickle-up. The test was simultaneously a success and a failure. By preloading, the tube was kept at low speed, reducing clumping; this appeared to reduce the variation either side of the mean (to perhaps 0.03 or 0.04), however, as you might expect, it also appears to have defeated zero-tracking, so drift accumulated and the overall variation was no better (with the potential for unchecked drift leading to much more variation). I had some ideas for other tests, but by this time my own dispenser was up and running so I stopped working with the CM.


    [​IMG]
     
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  5. Twoboxer

    Twoboxer Silver $$ Contributor

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    I calibrated both my Chargemaster and my A&D with the same set of weights (2 x 50g). At that point they have both proven their displays show the same 100g for what I told them was a 100g weight. (That includes the proofing re-weigh of the calibration weights.)

    Having thrown perhaps 1k short-stick powder charges from a CM and trickled up on an A&D FX120i, about 80% were +/-0.06gr from what the CM said they were. The remaining 20% would show an occasional +/-.16gr.

    The problems with the CM are NOT that it weighs grossly incorrectly when working right. Rather, they include the scale reacting badly to noise and the dispenser not being programmable to wait long enough for the scale to settle down before it calls "final".
     
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  6. rox

    rox

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    Were these charges with the largest deviation indicated by the CM as having the correct weight (i.e. matching the CM setpoint), or are you including in your analysis charges that the Chargemaster itself indicated were 0.1 over or under?
     
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  7. Willow

    Willow

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    My Chargemaster Lite was -0.2gr to +0.2gr accurate. It's back in the box now as I have a V3 Autotrickler.
     
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  8. damoncali

    damoncali Bullet Maker Site $$ Sponsor

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    Two things:

    1. A chargemaster’s performance is highly dependent on powder. Optimal settings change when you change powder. This impacts both speed and precision.

    2. there seems to be a lot of confusion/miscommunication over the accuracy/precision of the scale alone (which in my experience is pretty good) vs the accuracy/precision of the charging system as a whole, which is less good. It’s a matter of hitting your target weight vs believing the final weight. Two totally different things.
     
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  9. JimSC

    JimSC

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    In post # 16 I clarified it that was Varget, I will run a couple more of those tests. I will use SC 4831 and BL-C(2)
     
  10. rjtfroggy

    rjtfroggy Gold $$ Contributor

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    I have an original Charge Master and it is pretty darn accurate. I use IMR powders and calibrate twice before I start, set my desired load then start dropping loads. I go from the RCBS scale to a 505 and the weights are normally right on the money according to the two scales when they are over/under the set drop it is usually by only 3 or4 kernels depending on the powder.
    Now I don't know about long range because I don't shoot it but at short range BR I certainly can't see or shoot the difference between a dead on load or one that is off by a couple of kernels.
    I like mine, and am looking for another dispenser so as not to have to empty and refill for the two different powders I am using at the moment.
    These were all made by Pact and are now discontinued so finding a new one isn't going to be easy.
     
  11. CharlieNC

    CharlieNC

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    It really is not that difficult. Adjusting the tuning parameters such that trickling dispenses dead slow is free. Scrounging around to find
     
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  12. JimSC

    JimSC

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    Did 2 more tests this morning. Both the Chargemaster and the A&D 120 had been left on all night. The only mod to the CM has been the soda straw trick. Keep in mind that RCBS claims a accuracy of plus or minus .1 gns.

    rcbs cm 2.jpg

    using BL-C(2) a fine ball powder and the CM set to 30.0 the AVG was 29.97, STD DEV 0.03, Max 30.06, MIN 29.92, ES .014

    Next was 4831SC another stick With the CM set to 30.0 AVG was 30.05, STD DEV 0.22, MAX 30.94, MIN 29,90, ES 1.04

    I also timed the 25 charges of 4831SC by transferring the charge between 2 pans and immediately placing the first pan back on the CM so it could be auto charging. Time was 11 min and 46 seconds to dispense 30 charges or about 28 seconds per charge which falls right in with my earlier timings. I can trickle to within plus or minus a kernel of Varget while the CM is dispensing the next load

    edit - my opinion is the CM works perfectly well but you do need to double check if you are using a stick type powder. Occasionally a charge will be off considerably. A cheap battery powered scale such as Gem 20 is well worth the money
     
    Last edited: Jan 6, 2020
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  13. rsmithsr50

    rsmithsr50

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    you cannot test the accuracy of a 0.1 scale with another 0.1 scale. which one is right ?
    you need a scale that is one order higher, 0.0x to test with.

     
  14. rsmithsr50

    rsmithsr50

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    so during your test no charges were outside the ones you listed ? I am never so luckie
    I have a lite, not a cm.
     
  15. JimSC

    JimSC

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    I recorded each and every charge, no charges were excluded. I was very careful not to jar the machine this morning and pulled the pan within a couple of seconds of the beep. When a pan sits for any length of time I have noticed a few extra kernels will fall into it and occasionally I need to blow a kernel or two off the platform before replacing the pan. This is a Chargemaster 1500, bought around 2010.
     
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  16. dgeesaman

    dgeesaman Gold $$ Contributor

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    Agreed.

    To that end, I have a CM Lite and bought a manual trickler so that I could use the CM to charge to (target - 0.1 gr) and manual trickle until a kernel tipped it over the target mark.

    I ended up giving away the manual trickler after buying an Entris scale and AutoTrickler. For my current shooting, the new system is amply accurate on both measurement and charge dispensing. But again when I want to dial up kernel-perfection, I charge a hair low and add kernels to reach my target. Same game, just with the decimal point shifted over.
     
  17. Twoboxer

    Twoboxer Silver $$ Contributor

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    No charge was accepted unless the Chargemaster said it was on target.
     
  18. bichettereds

    bichettereds Gold $$ Contributor

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    My chargemaster will routinely over throw without the straw mod. I should also have clarified all my testing was done with N133 powder, and I got zero over throws (all read 30.0 on the RCBS scale).
     
  19. mike a

    mike a 6BR Rocks Gold $$ Contributor

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    How about if you want 30.0 grains you set it to 29.8 and trickle the last .2? Also I've only ever used D.C. volts. Can't leave it on 24 hrs. How about AC for 24 hrs then quickly switch to D.C.? Mike
     
  20. JimSC

    JimSC

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    I just set mine to target weight then if it is a bit over I pull a couple of kernels up the side of the "pan" with my fingers, most loads are a bit under so I pinch 1 or 2 kernels at a time from the dish and add them to the pan through the funnel. The pan came from a empty box of laundry detergent and the funnel and glass dish from Wally world. But it gets the job done and after some practice it is pretty easy to snag one or two kernels between the thumb and index finger. I can do about two rounds a minute, measured to the accuracy of the A&D which is plus or minus a kernel. One day I might buy some fancier gear but that day is not today, btw the loading block is home made also



    IMG_20200106_181319396.jpg IMG_20200106_181949832 - Copy.jpg
     
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