Scale inconsistencies?

[PracticalTactical]

I expect to upgrade to a more precise auto trickler scale down the road, but I want to understand what I observed in the meanwhile.

If you are a precision long range shooter, I would recommend that instead of buying an auto trickler, that you spend your auto trickler dollars on a better scale and if you don't have one already, a mechanical powder thrower.

If you think of the accuracy capability of any automated system, it will use a lower grade scale than you could purchase for the same dollars but without the automation.... Then you will have effective 3 decimal place accuracy.

But the real benefit is that when your 3 decimal place (in grains) drifts, it may drift by 1/5th of a kernel of varget. When a 2 decimal place scale drifts, you will have no idea until it has drifted at least 1 kernel.

You may be thinking that's no big deal, but its a bigger deal than most probably realize as there is a difference between what a scale displays and what the actual weight is. When you factor that in over a hundred rounds I have found in my testing that 1 decimal place scales are accurate to about four tenths of a grain at best. Two decimal place scales are accurate to 1/5th of that or 0.08 grains, and a three decimal place scale is accurate to on tenth of that or 0.008 grains.

If you translate such a weight variance to velocity spreads you can calculate the vertical dispersion that is inherent to the error in scale accuracy. By my math at 1000 yards, a 6BR will have 1.8 inches of more vertical dispersion when a 2 decimal place scale is used than if a 3 decimal place scale is used.

That may not resonate as relevant for plate shoots but 1000 yard BR guys and F Class shooters should take note.

In case you are wondering, I use a Vibra HT 220 with internal calibration to test the accuracy of scales in each category that I have had in the past, so I'm not just making stuff up or repeating something I read somewhere on the internet.

 

[Rocketvapor]

Finished prepping some cases, 6mm Hagar converted to 22 Nosgar, total spread of the 51 cases is +/- 1/4 grain sorted light to heavy, selected 51 primers by weight, WSR, for some break in loads for a new barrel for the wife to try @ 600 when the weather warms up. Gonna use medium loads, with a 0.2 grain spread per ten rounds with 75 AMAX (got a 3000 box through a shipping mistake and they didn't want me to ship BULLETS back to them ).
These will go into the fire formed once fired pile and a load fine tuned for ELD 88's, loaded long.
Will use CCI 450 primers and IMR4350 and Staball 6.5 powders for load development.

The entire process, Case, Primer, Bullet, Charge, will use my $46 Chinese digital scale, in my KLAS
(Kitchen, Lab, Armory, Shop)
More like a science project than reloading

 

[JFrank]

If you are a precision long range shooter, I would recommend that instead of buying an auto trickler, that you spend your auto trickler dollars on a better scale and if you don't have one already, a mechanical powder thrower.

If you think of the accuracy capability of any automated system, it will use a lower grade scale than you could purchase for the same dollars but without the automation.... Then you will have effective 3 decimal place accuracy.

But the real benefit is that when your 3 decimal place (in grains) drifts, it may drift by 1/5th of a kernel of varget. When a 2 decimal place scale drifts, you will have no idea until it has drifted at least 1 kernel.

You may be thinking that's no big deal, but its a bigger deal than most probably realize as there is a difference between what a scale displays and what the actual weight is. When you factor that in over a hundred rounds I have found in my testing that 1 decimal place scales are accurate to about four tenths of a grain at best. Two decimal place scales are accurate to 1/5th of that or 0.08 grains, and a three decimal place scale is accurate to on tenth of that or 0.008 grains.

If you translate such a weight variance to velocity spreads you can calculate the vertical dispersion that is inherent to the error in scale accuracy. By my math at 1000 yards, a 6BR will have 1.8 inches of more vertical dispersion when a 2 decimal place scale is used than if a 3 decimal place scale is used.

That may not resonate as relevant for plate shoots but 1000 yard BR guys and F Class shooters should take note.

In case you are wondering, I use a Vibra HT 220 to test the accuracy of scales in each category that I have had in the past, so I'm not just making stuff up that I read somewhere on the internet.

While I agree in part that a sharper knife cuts cleaner, what I see is that one kernel or .02 gr doesn’t seem to make a difference at 1000 yards but .1 or 6 kernels will and that may not be in vertical dispersion rather any direction.
We tune for exit timing at that distance looking for overlapping charges that group cleanly and true that small vertical dispersion is desired a well tuned rifle will share the point of impact despite an increase in charge.

 

[PracticalTactical]

While I agree in part that a sharper knife cuts cleaner, what I see is that one kernel or .02 gr doesn’t seem to make a difference at 1000 yards but .1 or 6 kernels will and that may not be in vertical dispersion rather any direction.
We tune for exit timing at that distance looking for overlapping charges that group cleanly and true that small vertical dispersion is desired a well tuned rifle will share the point of impact despite an increase in charge.

Don't confuse readability with the actual accuracy of the scale.

A scale that displays to 0.02 grains is not accurate to 0.02 grains. As I stated above, its closer to 0.08 grains over a hundred rounds. That's almost a tenth of a grain error and at least 4 kernels of Varget.

I say over a hundred rounds but its much less than that, I just don't want to get into a debate over some cheesy 3 load comparison on a 10 minute YouTube video that was edited to exaggerate the performance. I literally cringe when I watch the Ultimate Reloader scale reviews... OMG. You can literally watch him add 3 kernels of varget (0.06 grains) to get his 2 decimal place scale to notice the change on video.

 

[RegionRat]

I literally cringe when I watch the Ultimate Reloader scale reviews... OMG. You can literally watch him add 3 kernels of varget (0.06 grains) to get his 2 decimal place scale to notice the change.

Yup.
While Gavin has shown some real skill with his work, from time to time it seems like some things he does are half baked or rushed.

In some places, he goes into great effort to get good measurements and collect enough data to show how things really are, but when it comes to scales I have yet to see him slow down and do the homework. Compared to how much is spent on some of his other instruments, a decent set of check weights is trivial.

 

[JFrank]

Don't confuse readability with the actual accuracy of the scale.

A scale that displays to 0.02 grains is not accurate to 0.02 grains. As I stated above, its closer to 0.08 grains over a hundred rounds. That's almost a tenth of a grain error and at least 4 kernels of Varget.

I say over a hundred rounds but its much less than that, I just don't want to get into a debate over some cheesy 3 load comparison on a 10 minute YouTube video that was edited to exaggerate the performance. I literally cringe when I watch the Ultimate Reloader scale reviews... OMG. You can literally watch him add 3 kernels of varget (0.06 grains) to get his 2 decimal place scale to notice the change on video.

I don’t know who you are referring to in a video but I do know what I see tuning at 1000 yards.

 

[Rocketvapor]

Probably my cheesy video
Don't have the bandwidth to upload more than a couple of minutes.
Nap time for the old guy.

 

[JFrank]

Probably my cheesy video
Don't have the bandwidth to upload more than a couple of minutes.
Nap time for the old guy.

No worries, I will confess to not watching it.

 

[acloco]

Of interest, or debate.....controlling neck tension, is by far more rewarding on the paper, regardless of distance, than 1, 3, or 6 kernels of powder.

But, you do need to believe in your scale.

 

[1bamashooter]

I went ahead and grabbed this one .

We have one similar at work and it drifts terribly even in an enclosure, hope yours is better.

 

[Rocketvapor]

The original point of this thread was to evaluate/eliminate differences in scales. Buying a better scale is one fix. Accepting the accuracy you have is another. Testing with really good weights is another.

Powder charge is one variable. Knowing charge variations are small enough to be considered insignificant WILL help downrange performance. I didn't think weighing primers had any merit until I saw actual test results. Various case and loaded cartridge dimensions are other variables. Compensating for environmental conditions and so many other things contribute to good or bad shots.

But, this is about accuracy of powder charge. If you survey the market, more $$$ is spent on charging than neck tension, trimming, and annealing combined. Someone thinks it's important.

My beam scale is as accurate as advertised. Pictured is a 10 gram (154.32 gn) on my beam scale indicating 154.3 gn, and my digital, tared and it flickers from 154. 30 and 154.35 gn, but in carats mode (5 carats = 1 milligram) it flickers from 50.000 and 50.005 ct.
The weight used was measured against an ASTM Class 1 10 gram standard with multiple transpositions to an accuracy of a little more than +/- 1mg. I also use 1 and 2 gram weights to check calibration for powder charges.
Hardly ever have to recaibrate the digital @ 50 grams. Scale factor seems to be very stable. This one example seems to be very repeatable. The scale will auto zero 1 or 2 counts, if zero indicates anything, I press the tare button. Charging 100 cases, with an extra 10 check weightings adds very little time.

My scales compare quite favorably. My measurement method detects/eliminates MOST drift. It takes a few seconds to periodically check the digital.

My issue with the beam scale is not with tossing a predetermined charge, but actually weighing something.
Sorting cases, bullets and primers with a beam scale isn't really practical.

Sounds like you need both.

 

[Rat Rifle]

We have one similar at work and it drifts terribly even in an enclosure, hope yours is better.

Is it in the presence of fluorescent lights ?

 

[AzMandella]

We have one similar at work and it drifts terribly even in an enclosure, hope yours is better.

Well i will test it immediatly and if it drifts I will return it .

 

[JFrank]

All the E scales I can afford drift.

 

[1bamashooter]

Is it in the presence of fluorescent lights ?

LED

 

[Homerange]

LED

Conceivably the worst due to the typically EMI noisy SMPS they are powered from.
They can radiate garbage for several yards and potentially upset sensitive equipment that isn't sufficiently protected from conducted EMI or airborne RFI.
Some LED lighting is garbage in this respect and others are OK but the only way to know is to become acquainted with another rabbit hole of knowledge and understanding ............

 

[AzMandella]

Well i will test it immediatly and if it drifts I will return it .

I am replying to this because I received my scale and put it through it's paces . The scale is an Ohaus Scout SPX123 . I also have a Ohous 5 0 5 and a Hornady G3 1500 . All new . I also purchased a Class F test weight set that is from .5grn to 100grn. I turned on and let the digitals warm up and zeroed the beam scale . I calibrated the Ohaus with the 100g weight it comes with and the Hornady with the 10g weight it comes with . I then used the powder pan that the came with the Hornady for both electric scales and zeroed them . For the next 4 hrs off and on I tested accuracy and repeatability . I removed the pan and replaced it at least 100 times . Went back to zero every time . Then started to place and remove the test weights from lightest to heaviest . The .5grn thru 5grn weighed dead on . I also removed and replaced the pan with the weights still in them and it always read the same . Once I started with the 10grn , 20grn , 50grn , 100grn and 200grn weights they all read a little off of their advertised weght . the 20grn was 20.06 .and the 50grn was 50.22 . So I then weighed them on both the beam scale and Hornady and they read exactly the same . So i then started mixing weights to make 25.5grns using the .5grn + 5grn + 20grn and it weighed dead on at 26.1 that includes the .06grn difference of the 20grn weight . In conclusion I find this scale to be very accurate and repeatable . I did not see any noticable drift nor did i have to rezero it . Can't wait to see how consistent the Harrrels powder measure I bought is going to be . Here is the pictures of the Beam and Ohaus reading the same with the 50grn weight . I didn't take a pic but the Hornady read 50.2 .

 

[Rocketvapor]

Looks like your scale is better than your check weights