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Posted: 10/17/2016 2:13:44 AM EDT
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I'm working up some .30-06 hunting loads and got a little curious about the technique others use for measuring charges.
First off, when working up a ladder of new loads to test, do you individually weigh each charge or use your scale to dial in a powder measure for each weight and then throw however many charges you want for that particular weight? Another question I have relates to beam scale technique. I have a Ohaus made RCBS 505. My technique for weighing charges is to first level and balance the scale. Then I set the weight I want on the beam. Finally, I add powder to the pan using a scoop and trickler until the scale is balanced. Is that a valid technique for weighing charges or should I start with the scale zeroed out, then add powder, and finish by using the weights to rebalance the beam. Or does it not really matter? |
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Quoted:
I'm working up some .30-06 hunting loads and got a little curious about the technique others use for measuring charges. First off, when working up a ladder of new loads to test, do you individually weigh each charge or use your scale to dial in a powder measure for each weight and then throw however many charges you want for that particular weight? Another question I have relates to beam scale technique. I have a Ohaus made RCBS 505. My technique for weighing charges is to first level and balance the scale. Then I set the weight I want on the beam. Finally, I add powder to the pan using a scoop and trickler until the scale is balanced. Is that a valid technique for weighing charges or should I start with the scale zeroed out, then add powder, and finish by using the weights to rebalance the beam. Or does it not really matter? I weigh each individual charge using the RCBS Chargemaster Combo then confirm with a second digital scale. If I'm going to be testing in 0.2gr or 0.3gr increments of powder, it just makes sense to me to be as precise as possible with the measurements. A powder measure will be +/- 0.1gr and possibly more if it's a powder that doesn't meter particularly well. So if I was trying for (e.g.) 23.0, 23.2, 23.4, 23.6, 23.8 and 24.0gr charges to test, the powder measure could easily throw a particular charge at almost the next increment up/down and I'd be wasting my time. This becomes slightly less important if you're aiming for charges in 0.5gr or bigger increments of course, but given the minimal number of rounds that are loaded for development, I'd still rather know that I'm being as precise as I can be with them. |
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Quoted:
My technique for weighing charges is to first level and balance the scale. Then I set the weight I want on the beam. Finally, I add powder to the pan using a scoop and trickler until the scale is balanced. This is the right way, also the way I do it too. I set my powder measure up to throw just under my target weight then trickle up til it's exact. I weigh every charge, there's no sense testing if every charge isn't the same. There's a lot of other things that can vary why add another with inconsistant charges ? |
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Quoted: When trickling up to balance, it doesn't hurt to either bump the scale and let it re-settle or simply remove the pan and put it back on and let it re-settle. Give it a try and see if you get the exact same reading. Motor  |
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I hate trickling, so I get the charge weight set on the powdermeasure and drop my test loads right into the case. If a load is so picky that trickling charges makes a difference at 200yds or less (which is rare), then I want no part in it. Knowing the best case outcome is of no value to me. I'd rather know what the load will do with maximum typical variations. To that end, I do a comfirmation run on promising loads using one group with half the charges hand weighed to 0.3gr light and the other half heavy. These go into a special batch of brass that I have set aside (off center flash holes and wide on weight variation--heavy charges go in heavy cases). If it still shots OK (in the 1MoA neighborhood), then it's G2G. I always upset the pan a little after I've added powder and let it settle out. |
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Quoted:
So, if the readings are different....which one is correct? Quoted:
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When trickling up to balance, it doesn't hurt to either bump the scale and let it re-settle or simply remove the pan and put it back on and let it re-settle. Give it a try and see if you get the exact same reading. Motor I would confirm that the scale is zeroed as accurately as possible and take the empty pan on and off the scale at least twice to make sure the zero is repeatable. After that, I'd trust the reading I got that's repeatable (again taking pan with charge on and off at least twice). |
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.......... snip.........
I weigh each individual charge using the RCBS Chargemaster Combo then confirm with a second digital scale. If I'm going to be testing in 0.2gr or 0.3gr increments of powder, it just makes sense to me to be as precise as possible with the measurements............... snip.......... You're correct. The Chargemaster isn't precise enough for doing scientific ammo development. Like you, I also confirm and fine tune each charge on a second scale with .02gr resolution. When you think about it, precision loading is potentially more important during development than when you're making competition ammo. Often times you're looking for tiny differences in performance when you test things like seating depth or neck tension. Therefore, you MUST have confidence that your charge weights are as accurate as possible while you are testing various parameters which are under your control. Later on you might decide that your best recipe is so forgiving that you can relax your procedure a little bit and still enjoy winning performance. But first you gotta' gather accurate data and study it in order to find out what's what. On the other hand, some folks advocate just finding something which works OK and finishing load development as quickly as possible. Generally speaking we don't see them in the winner's circle very often. |
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Motor1 is correct... weigh your powder and then bump the pan to get it moving and let it resettle again- that will give you a better reading and you might find that trickling (or finger tapping on a Lee scoop) until the weight is just UNDER the line produces the desired weight after the finger tap to the pan (not hard). When setting up the powder measure with a scale, I like to throw 10 charges in a row that weigh dead on before I start throwing into cases.... then I check every 10-20 depending on the powder used. |
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And if you see much difference between several readings of the same sample, you chalk that up to what is part of the uncertainty of your scale.
You should try and get some check weights and work on a technique that you can repeat with a known check weight. It pays to be honest with yourself and explore what makes this better or worse. Then you focus on how getting powder to go through your loading process works best for you. I would say most .30-06 hunting loads should be good with the capabilities of a beam scale or just about any digital scale. With game on the order of deer or elk, you probably will be holding your shots to less than 500 yards in order to get good terminal performance and penetration. It is when you get into F-Class or distances out past 600 yards when your scale needs to have very low uncertainty to minimize the speed variation of your loads. You should be okay for hunting within the capabilities of your beam scale. Many other factors will have to be brought up to higher performance levels to benefit from a better charge weight, so for now learn to minimize the variation with your beam scale and see what the SD of your average speeds look like under different weather conditions. |
| I do the above but take it a step further. 1 make sure you don't have a fan or even the air conditioning running or near you. I use the rcbs powder check weight set to my charge weight. also make sure you sit in the same spot especially angle as sometimes angles can make it look different. I drop a few tenths low and trickle up to my desired weight. |
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Quoted:...
Is that a valid technique for weighing charges or should I start with the scale zeroed out, then add powder, and finish by using the weights to rebalance the beam. Or does it not really matter? If you did this, you would never know when to stop adding powder. You would have to get about a one in a million correct guess for the weights to balance the beam with the amount of powder you want in it. The only reason you would ever use this technique would be to determine the actual weight of an item where you can't control it, only check it. Let's say you wanted to weigh brass, or bullets. You must zero to account for placement of your scale, and to make sure you have a repeatable zero. Then you set your desired weight. Then you add your product. I check my zero by bumping the pan. If it returns to the same zero at least two out of three times, I call it good. When I dump the powder in the pan, it usually mounds up in a general spot. I check to see if the scale returns to zero, then I raise the pan and swish the powder so it spreads more evenly in the pan and check again. You don't have to go that far. You can just bump it again if you prefer. |
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