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Old January 21, 2005, 11:43 AM   #1
bill k
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Difference in scales

I got beat shooting a couple days ago, it'll happen again someday but I think I found my problem. I currently use an RCBS 5-0-5 scale. I've always been concerned about the accuracy lining up the two lines to get your weight. I borrowed a digital scale and found the difference in weight very between .1g to as much as .3g. I'm using 77.0g of IMR 4350 which amounts to between 4 and six indiviual granuals.
Does anyone have an idea how much this would effect accuracy. I'm shooting a 300 ultra mag load.
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Old January 21, 2005, 11:46 AM   #2
Edward429451
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I'm no competition shooter or anything but from what I understand, it should be zilch difference. It's more about volume than weight.

Make up some loads both ways and compare.
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Old January 21, 2005, 05:03 PM   #3
dodgestdshift
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Bill:

Did you ever consider the possibility that the digital is the scale with the variance?
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Old January 21, 2005, 05:20 PM   #4
DAVID NANCARROW
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Bill-are you finding the differences while using check weights?
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Old January 21, 2005, 05:54 PM   #5
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You need to watch out for drafts and breezes in the room. They'll throw things off. If you weight the same drop of powder three times, you shouldn't be off by more thna 0.1grs. If it's out, you may want to clean the fulcrum things.

I shoot competitive highpower rifle and do pretty good at it. I can live with up to 0.3grs variation from one charge to the next (although I use a Harrell measure which is rarely outside of 0.1grs). At short range (300yds and less), it really doesn't matter. At 600yds, it might matter. I do generally weigh each charge for 600yds (as do many if not most highpower shooters), but I must say that my personal best score was with as-thrown charges (194-10x).

Additionally, some loads will be more sensitive to variation in charge weight than others. I do all my load development measuring only every 5th charge. If a load only shoots well if I measure each and every one, then I'm not interested in it.

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Old January 21, 2005, 08:41 PM   #6
Robert M Boren Sr
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I talked to a competition shooter and he said that a variance of .1 to .2 either way is acceptable in competition shooting.
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Old January 21, 2005, 10:19 PM   #7
bill k
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Thanks for the imput, I guess it's back to the drawing board. I just got back from my reloading supply shop. I spent $100.oo on different bullets, powder, and primers. Whoever said you save money reloading is full of bull.
It's still fun. Hopefully I'll win next week.
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Old January 22, 2005, 07:29 AM   #8
WESHOOT2
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required

Scale weight check set, used religiously.

Very minor variances in charge weight rarely seem to make much difference over the chrono, even in handgun loads.
Same with OAL.

Hmmmm........
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Old January 22, 2005, 09:49 AM   #9
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Bill, I second the recomendation of check weights. You can get a set made by RDCS and keep them around for occasional calibration checking.

Another very importand thing to consider is how you are looking at your balance beam scale. Are you bending over to look at it? The best place to put your scale is on a high shelf at eye level (or a not-as-high shelf if you work sitting down). It is much easier to read accurately that way. If you are presently bending down to look, you will be amazed how much better your "new" scale will be when placed at the correct height.
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Old January 22, 2005, 03:08 PM   #10
Robert M Boren Sr
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Yes, I forgot to mention that, I have check weights also. That takes the guess work out of it. One thing too, it helps to keep the scale wiped of the dust does make a difference of how it opperates even if zeroed.
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Old January 22, 2005, 07:18 PM   #11
Edward429451
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If you don't have check weights, you could check your scale against a friends. Thats what I do sometimes. It checks his and mine at the same time. Also, if you have have something of a known exact weight that you could set aside for this purpose, that works too. I swage a little and have bullets of exact weight so I never felt the need to buy check weights.
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Old January 22, 2005, 07:39 PM   #12
bill k
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I guess I'm stupid, may wife says it all the time for the firearms I buy. OK, I have check weights that say 30, I guess it to be grams. On my 505 scale its reads 464.3 grains, on the digital it reads 461.7grains. The digital reads 29.92 grams when I change the units to measure grams.
Are my scales ok? Or are they off?
Or am I to critical, blaming my scales for losing the bet shooting? I hate losing!!!!!!!!!!!!!
They also, both of them seem to go to the same reading every time I recheck.
Thanks for all the answers.
Bill
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Old January 22, 2005, 08:29 PM   #13
Edward429451
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Bear with me, I'm no mathmetician...

437.5 grains = 1 oz
28.35 grams = 1 oz

437.5 / 28.35 = 15.43 grains per gram so;

15.43 X 30 = 462.9 grains is what your scale should read for a 30 gram checkweight.

464.3 - 462.9 = 1.4 grains off (505) heavy.
462.9 - 461.7 = 1.2 grains off (digital) light.

Something's wrong. I have a 505 and it has a 'personality', which I'm used to. If I zero it and throw on a check bullet and its not right on the money, I know that one of the adjusters isn't exactly down in the groove like it should be. Usually the 10 grain adjuster. I give it a tap lightly and it sinks into place where it should be and then its right on the money. Possibly yours is the same? I trust my old 505 more than any digital scale. Just cause its digital does not mean that its automatically more accurate. Hope this helps.
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