Question about powder scales

Discussion in 'Reloading' started by meatyrem, Sep 27, 2011.

  1. meatyrem

    meatyrem Well-Known Member

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    I have been having a problem with my powder scale. At one time it will measure one weight and then it will measure another when I put the same amount of powder in the pan. It will be off by 1 to 1.5gr at times. No matter how many times I put the powder back in the pan and remeasure it, it comes up with a different reading. It's a Cabelas XT-1500 digital scale. I'm sending it back as I'm dissapointed with it. Anyone have suggestions on better scales? I was looking at the rcbs 750 or the lyman 1000.
     
  2. Cover Dog

    Cover Dog Active Member

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  3. winmag

    winmag Well-Known Member

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    R.C.B.S. 505 beam scale. Works in the garage at -6 deg in dead of winter to Las Vegas heat waves in summer, & always reads the same. Handy to have if for no other reason than keeping your digital scale honest. I know its a bit slower, but I wouldnt feel comfortable without one on my loading bench. JMO
    Your digital has a 1 1/2 gr margine of error? That's enough to get someone killed if your running top end loads. I would not shoot anything it has measured for safety sake. Please be carefull. Pulling bullets is WAY cheaper than a visit to the E.R.
     
    Last edited: Sep 27, 2011
  4. Trickymissfit

    Trickymissfit Well-Known Member

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    The RCBS scale is a good scale. Built by PACT in Texas, and not by China.
    gary
     
  5. Trickymissfit

    Trickymissfit Well-Known Member

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    my beam scale went to the flea market like they all need to go. But if you just gotta use a Model T scale, then at least buy a Ohaus 304. I've done a good bit of checking on the accuracey of beam scales and digital scales over the years in a lab enviourment. The margin of error for the ones I tested were about five hundreths of a grain on one battery powered one and about half that on several Pacts. Used a $10K master scale and then another used to check the master.

    gary
     
  6. kc0pph

    kc0pph Well-Known Member

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    I use a 10-5-10 Scale (i think) from RCBS. Ive calibrated it using lab grade weights. Before i load my .270 150 gn Sierra SBT I put on a 50, 5, 1, gn weights and make sure its accurate. Never had a problem. With H4831 I can see individual grains trickle down.

    If your going to spend the time preparing your brass, and plan to shoot under 50 rounds per shooting session you need a balance scale or a lab grade digital. Its the most accurate way to go. Well let me clairify its the most consistent way to go.
     
  7. winmag

    winmag Well-Known Member

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    I don't have a digital. I was talked out of buying one. Seems a split down the middle crowd. 1/2 say yes 1/2 say no way. I played it safe, but I have 0 personal experience with digitals. I bought the ol' reliable "dinosaur" as some call it. But she's honest. & I'll take slow & honest any day.
     
    Last edited: Sep 27, 2011
  8. winmag

    winmag Well-Known Member

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    First off I like my model T.
    Second I trust it.
    But I guess if your lab testing prooves otherwise to you then you have your trusted meathod, & I have mine, although I have no $10,000 scale to check it against, or even a lab or lab coat. I'm not knocking anyone's equipment. I never started down that road. I have asked many trusted shooters & reloaders on this forum about digitals. Many like them, & many you couldn't give one to. I don't belive my bank account would not allow me to play with your caliber of toys, so I got what is generally considered the trusted go to scale for accuracy & affordability.
    But hey, that's just me. If 1 1/2 grains with his particular scale doesn't make a guy sceptical, go ahead on er'. I was just concerned for the guys safety.

    As far as the flea market goes... Wow man. Who Peed in your cheerios today? That's low.:)
    Tricky, your almost as opinionated as I am, haha. So how do I find info on these Ohaus scales? What price range are they in? Ill admit I do like my 505 scale, but having another trustworthy scale around keeps em all honest.
     
    Last edited: Sep 27, 2011
  9. danj

    danj Well-Known Member

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    I too use a beam scale and have total trust in it. Had one digital scale and didn't trust it so I sold it at a flee market!!:):) Just kidding. I use both. For my edge loads it's beam all the way.
     
    Last edited: Sep 27, 2011
  10. kc0pph

    kc0pph Well-Known Member

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    I have a set up for pistol charges in my 357 when i am not doing max loads to us a digital scale. Its really easy to hit the tare button and its super fast. I tare the scale to the case, then throw the powder in the case, then weigh it. All im looking for is a GROSS under or over charge. The way i see it is this. For sake of argument lets look at my 357 mag. At one time i ran it up to 7.8gn 231 with a 158 gn cast bullet. I had slight primer leakage and slight primer flattening (if i remember correctly.) Now if i use a scale with 1 1/2 margie of error, and trusted it i could come out with 9.3 gn of 231 in it. That is what you call a ruptured cylinder (although i think a 586 can take it, as it is a super strong 357), and a trip to the trash can or a gunsmith to get you a new cylinder/barrel installed.

    I think most can agree, if you are willing to spend some money on a scale that does not have error, and willing to protect the strain sensor in it then go for it. But for under 100-150 go with a beam balance. You CANT go wrong with a good RCBS scale.

    A note about the 505 scales, i have one it is junk. RCBS cheapened up the scales. Grab a good old 10-5-10 (i think it is).

    (My father deals a lot with electronics and knows a lot about electronic scales, when he calls me back ill post with the scientific explanation of why cheap (most scales under $400) digital scales are dangerous.)
     
  11. kc0pph

    kc0pph Well-Known Member

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    It comes down to resolution. In a beam balance your resolution comes down to the quality of the bearings. Even a beam balance with modest bearings has a great resolution. An electonic scale suffers from 2 defeciencies. The first is the resolution of the load cell/ strain guage and the sensors historesis. Also there is a compromised resolution that is purposly limits the electronics scale any more reslution that is specified. They dont want to get into the area where there might be ambiguity of the sensor. There is also historesis in the beam balance, and that is dependednt on the bearing system. Its typically very small, and usually smaller than whats used in the digital scale.

    Historesis is essentially a loop, and what it is is the difference between going through the upper limit and it being detected, then coming back down through that same point and being detected again. Typically in a digital scale it is not the same point. You can liken it to the fucnace thrrmostat by letting the house warm up above the temp and then letting it cool off below the tempature. In a mecanical scale you have to have a certain force before you will get past the friction in the bearing. It will be the same friction that stops it. Think of a wagon wheel.

    It just comes down to resolution and the ability to handle small changes. Cheaper scales just cant do that. Its very expensive to get a good load cell to measure 1/10th a grain. That is a small amount. Where as a beam balance a bearing is very cheap and stamping out parts is cheap as well. It is just important to verify zero.

    Take the time if you want precision and buy a beam scale, or blow 400 on an unneccecary digital scale.

    Even with a powder master (the automatic powder trickler) you should verify your charge on a quality scale.

    If you put too much weight on a scale that is designed to detect 1/10th a grain changes you will damage the load cell and make it unreliable.

    To answer the question above about the 1 1/2 gn variance its the friction it takes to move the load cell (compress the stain guage). Just by placing the powder pan on the scale with a different acceleration can change it. When i use my digital scale it is not uncommon for it to read several hundred grains when i am putting the pan on the scale. This is what will damage a scale.

    Hope this helps.
     
  12. meatyrem

    meatyrem Well-Known Member

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    It's funny (not really) but there are times when I get to the last tenth of a grain or two and there is no movement after I have trickled several single pieces of powder and still have it not register on this scale. It is goping back tomorrow.
     
  13. meatyrem

    meatyrem Well-Known Member

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    Appreciate all you that replied. Very helpful and informative. As I said that junk Cabelas scale is on it's way back. So frustrating when you trickle in 10, 12, 15 pieces (H-4831sc) and don't get a different reading. So by by. It's just hard to trust a digital scale now. So I will be looking around some more.

    Thanks to all with the help
     
  14. Trickymissfit

    Trickymissfit Well-Known Member

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    out of curiosity how did the lab grade check weights compair with the check weights from RCBS on your scale? I ran that same check like you and found that most check weights were off a little bit. A good set of lab grade weights should come with certification papers that will actually tell you their error. Somewhere in my stuff I have two sets of weights that I listed the error on them. I should have kept one of the lab weight sets for my own use as we must have had two dozen sets of them that nobody ever used. Probably ended up in the trash!
    gary