How Much Precision in a Scale is Required for Precise Weight-Sorting?

[PracticalTactical]

It's all about how fine you want to thread the needle.

If you want to sort primers, the FX120 will be of no value unless your primers are complete crap in which case, why bother.

If you want to sort primers, then a scale that reads to 0.002 grains is really going to help.

There's lots of love for the FX120 but there is nothing wrong with getting something ten times as accurate. It certainly wont hurt.

As said above conditions typically dictate scores, but if you get into a calm condition, then you will see the difference.

 

[GetReal]

As said above conditions typically dictate scores, but if you get into a calm condition, then you will see the difference.

I'm of the view - I could be wrong - that so long as I have decent but basic reloading equipment, I can improve my scores much more by learning to read conditions. And until I do that, spending $5,000 on whizz-bang reloading gear is cart b4 the horse.

 

[Rocketvapor]

Where did the op go?
What kind of shooting did HE have in mind?
I think a little more info up front would get him better answers.
Either pertinent answers or direct him to your podcasts.

 

[6bra1k]

It's all about how fine you want to thread the needle.

If you want to sort primers, the FX120 will be of no value unless your primers are complete crap in which case, why bother.

If you want to sort primers, then a scale that reads to 0.002 grains is really going to help.

There's lots of love for the FX120 but there is nothing wrong with getting something ten times as accurate. It certainly wont hurt.

As said above conditions typically dictate scores, but if you get into a calm condition, then you will see the difference.

sorry but this is not true.
shooters on these forum have sorted , shot and PROVEN IT WORKS.
THAT is facts, data targets down range...NOT AN OPINION

 

[South Pender]

It's all about how fine you want to thread the needle.

If you want to sort primers, the FX120 will be of no value unless your primers are complete crap in which case, why bother.

If you want to sort primers, then a scale that reads to 0.002 grains is really going to help.

There's lots of love for the FX120 but there is nothing wrong with getting something ten times as accurate. It certainly wont hurt.

As said above conditions typically dictate scores, but if you get into a calm condition, then you will see the difference.

Thanks, PracticalTactical. That's the kind of information I was looking for. I'm not really interested in sorting primers, but I would like to sort brass accurately and, of course, powder charges. Do you think the FX120 is adequate for this? And can you suggest a more accurate scale (and ideally affordable) that reads to the .002 grains you mentioned?

 

[DocCarbon]

Practical precision scales come at a far more affordable price than in years past .

As most all of us know precision comes at a price ,scales are NO different . There's $50.00 scales and there are $50,000 scales . However for ALL practical shooters from Hunters to BR shooters ,there are affordable scales .

Some Decent sensitive scales which require draft shields and are Certified Legal Trade along with weighing in several modes can be had for $200.00- 300.00 or less just depends on YOUR preference and brand .

Another point I'd like to bring up is calibration ,precision weight sets or Known value individual weights . What good is a scale if it's Not calibrated or repeatable !. About as good as a linen patch down your 6mmPC ,IMO .

This website has a Nice selection and gives detailed information for Class certification . BE INFORMED before wasting time and money on inferior quality scales . I Don't endorse any websites or products that I've personally not dealt with ,so Same goes here it's for YOUR INFORMATION and appears to be a Good sites .

https://www.oldwillknottscales.com/precision-scales.html?sort=PriceAsc&&pi=2

This scale is more scale than 100% of you will ever use .

https://www.oldwillknottscales.com/my-weigh-ibalance-401.html

Anylitical and Pharmaceutical scales are real precise and come with a price tag . Speaking from more years of experience than I care to reveal , a Quality lessor scale is far more useful when measuring loads or sorting cases than High tech High Priced analytical Sartorius .

I have a #10-15 year old Sartorius Cubis which New ran near $10K . I still use Ohaus Balance and Electronic . Once I set My scales on My bench ,they NEVER move except for Twice a year, for cleaning and are set Exactly back where they were and Re-calibrated . I actually have drill points on the bench to mark their positions .

Here's a New Sartorius Cubis ll Ultra and it runs nearer $36K

https://www.scalesgalore.com/Sartorius-Cubis-II-Ultra-Micro-Balances-00001mg.cfm

https://www.scalesgalore.com/sartorius.htm

Why am I anal about scales ?, Because I got burned ( figuratively speaking )at work once ,by Not calibrating tank scales ; It Never happened to Me again .

 

[South Pender]

Practical precision scales come at a far more affordable price than in years past .

As most all of us know precision comes at a price ,scales are NO different . There's $50.00 scales and there are $50,000 scales . However for ALL practical shooters from Hunters to BR shooters ,there are affordable scales .

Some Decent sensitive scales which require draft shields and are Certified Legal Trade along with weighing in several modes can be had for $200.00- 300.00 or less just depends on YOUR preference and brand .

Another point I'd like to bring up is calibration ,precision weight sets or Known value individual weights . What good is a scale if it's Not calibrated or repeatable !. About as good as a linen patch down your 6mmPC ,IMO .

This website has a Nice selection and gives detailed information for Class certification . BE INFORMED before wasting time and money on inferior quality scales . I Don't endorse any websites or products that I've personally not dealt with ,so Same goes here it's for YOUR INFORMATION and appears to be a Good sites .

https://www.oldwillknottscales.com/precision-scales.html?sort=PriceAsc&&pi=2

This scale is more scale than 100% of you will ever use .

https://www.oldwillknottscales.com/my-weigh-ibalance-401.html

Anylitical and Pharmaceutical scales are real precise and come with a price tag . Speaking from more years of experience than I care to reveal , a Quality lessor scale is far more useful when measuring loads or sorting cases than High tech High Priced analytical Sartorius .

I have a #10-15 year old Sartorius Cubis which New ran near $10K . I still use Ohaus Balance and Electronic . Once I set My scales on My bench ,they NEVER move except for Twice a year, for cleaning and are set Exactly back where they were and Re-calibrated . I actually have drill points on the bench to mark their positions .

Here's a New Sartorius Cubis ll Ultra and it runs nearer $36K

https://www.scalesgalore.com/Sartorius-Cubis-II-Ultra-Micro-Balances-00001mg.cfm

https://www.scalesgalore.com/sartorius.htm

Why am I anal about scales ?, Because I got burned ( figuratively speaking )at work once ,by Not calibrating tank scales ; It Never happened to Me again .

Great detail, DocCarbon. If I'm reading all of this correctly, I'm coming around to thinking that a scale good for .001 gram (.02 gn.) resolution (like the FX-120i) should be sufficiently precise for weighing cases and powder, although that was my original question. Is there any practical reason for any more precision for cases and powder? With this level of precision, I'm guessing that a group of, say, 10 cartridges all charged to the same weight of powder might, in fact, differ by up to about .06 gr. of powder. So when you charge your 6PPC cases with your .001 g. scale set to 31.0 gr., you might end up with the lightest charge being 30.97 gn. and the heaviest, 31.03 gr. I'm guessing that this level of charge-weight difference would not be accompanied by any discernible velocity differences. But do I have this right?

However, as PracticalTactical has noted, this level of precision would be completely inadequate for weighing primers. For this, I'm assuming that you would have to go to the .0001 gram (.002 gn.) scales. Unfortunately, this gets you into pretty pricey territory. Is there a .1 mg. scale that is as affordable as the FX-120i?

 

[Mulligan]

.001gram resolution is plenty for weighing primers.

Hell, my old tuned 10-10 works great for sorting primers.
It is well tuned and I use my iPad with the magnifier app to see the needle.

CW

 

[Mulligan]

After you sort the chubbies and skinnies out, just batch the rest into two or three batches and call it a day. In the end, do you really care what they weigh, as long as the 5 or 10 that are headed for the same bull are the same weight?
CW

 

[PracticalTactical]

sorry but this is not true.
shooters on these forum have sorted , shot and PROVEN IT WORKS.
THAT is facts, data targets down range...NOT AN OPINION

If it works with an FX120, then it will work ten times better with a scale that is ten times more accurate.

If you are realistic about primer weight variance, meaning have actually measured their weight on a 0.002 grain scale, then you will appreciate my point.

The weight variance of good primers is often inside the accuracy capability of an FX120 or equivalent. In which case you are sorting according to the error in scale accuracy instead of by primer weight.

In which case you can sort your primers only to that limit and you will get overlap between your groups. Suppose you have primers in groups of 0.02 grains, and there are 4 groups. Primers in any of those groups may actually be of identical weight based on 0.02 grain scale accuracy. AKA readability.

If you realistically want to sort primers to within 0.02 grains, you need a scale that has an error that is less than 0.02 grains... This is measurement and inspection 101.

 

[dannyjbiggs]

Wait !
No one uses a beam scale for sorting?

Not anymore. But last century, I used a RCBS 304 beam scale with much more speed and accuracy than you might think!

 

[Hengehold]

The answer to your question is discussed in great detail in the book by Brian Litz in his “Modern Advancements in long range shooting, vol II” with experiments and conclusions.

Easy to read and very interesting.

Modern Advancements Series

 

[6bra1k]

Great detail, DocCarbon. If I'm reading all of this correctly, I'm coming around to thinking that a scale good for .001 gram (.02 gn.) resolution (like the FX-120i) should be sufficiently precise for weighing cases and powder, although that was my original question. Is there any practical reason for any more precision for cases and powder? With this level of precision, I'm guessing that a group of, say, 10 cartridges all charged to the same weight of powder might, in fact, differ by up to about .06 gr. of powder. So when you charge your 6PPC cases with your .001 g. scale set to 31.0 gr., you might end up with the lightest charge being 30.97 gn. and the heaviest, 31.03 gr. I'm guessing that this level of charge-weight difference would not be accompanied by any discernible velocity differences. But do I have this right?

However, as PracticalTactical has noted, this level of precision would be completely inadequate for weighing primers. For this, I'm assuming that you would have to go to the .0001 gram (.002 gn.) scales. Unfortunately, this gets you into pretty pricey territory. Is there a .1 mg. scale that is as affordable as the FX-120i?

your mis reading or mis listening.
the ad fx120i is .02 grain with a .03 tolerance...that is not plus or minus .03

If it works with an FX120, then it will work ten times better with a scale that is ten times more accurate.

If you are realistic about primer weight variance, meaning have actually measured their weight on a 0.002 grain scale, then you will appreciate my point.

The weight variance of good primers is often inside the accuracy capability of an FX120 or equivalent. In which case you are sorting according to the error in scale accuracy instead of by primer weight.

In which case you can sort your primers only to that limit and you will get overlap between your groups. Suppose you have primers in groups of 0.02 grains, and there are 4 groups. Primers in any of those groups may actually be of identical weight based on 0.02 grain scale accuracy. AKA readability.

If you realistically want to sort primers to within 0.02 grains, you need a scale that has an error that is less than 0.02 grains... This is measurement and inspection 101.

read what i said....
sorting with an ad fx120i WORKS AT 1000 YARDS.
your OPINION is just that and since i doubt you shoot 1000 br, it has little value in this conversation.

 

[PracticalTactical]

your mis reading or mis listening.
the ad fx120i is .02 grain with a .03 tolerance...that is not plus or minus .03

read what i said....
sorting with an ad fx120i WORKS AT 1000 YARDS.
your OPINION is just that and since i doubt you shoot 1000 br, it has little value in this conversation.

So hang on a sec... You have a problem with my recommendation because I use a scale that is too accurate?

And based on that you conclude that what??? I'm a back yard plinker?

I've been shooting F Class since long before they heard of it in the USA, but you are correct, I don't shoot bench rest, sorry but I find it boring. No disrespect to those that enjoy the sport.

As for your assessment of the accuracy of the FX120, sorry but you are in dream land. At best it is plus or minus 0.03 rounded to even numbers which makes it plus or minus 0.04. It only displays even numbers. That's almost a tenth of a grain, in the real world. Add to that voltage fluctuations, the crappy load cell sensor etc. Hey, it's a nice value scale that's greatest value is the auto trickler, but it aint no analytical balance by any means.

At least be honest about it.

 

[South Pender]

your mis reading or mis listening.
the ad fx120i is .02 grain with a .03 tolerance...that is not plus or minus .03

Well, unfortunately, I flunked Measurement and Inspection 101, so what does .02-grain readability in a scale mean in terms of likely weight dispersion in a group of powder charges? Put more concretely, say I weigh 10 charges with this scale hoping for charge weights of exactly 31.0 grains. How much difference is there likely to be between the heaviest charge and the lightest, given the .02-grain readability precision quoted for the scale?

Edit. I've just reread PracticalTactical's last post and wonder whether the ± .04 gr. he mentions for the .02-gr. readability scale means that, in a large group of weighed charges--all weighed to 31.0 gr.--the spread might be something like 30.96 gr. to 31.04 gr. So first, do I have this right? And second, is this much variation likely to manifest itself in noticeable velocity variation? Obviously for light charges in the 20-30-gr. range, the effect will be greater than with heavier charges in the 50-60-gr. range.

 

[RegionRat]

Well, unfortunately, I flunked Measurement and Inspection 101, so what does .02-grain readability in a scale mean in terms of likely weight dispersion in a group of powder charges?

This could be a deep rabbit hole all by itself. I suggest that thread drift is a huge risk if we go too far away from sorting cases and end on sorting primers or the value of single kernel loading. YMMV

 

[6bra1k]

So hang on a sec... You have a problem with my recommendation because I use a scale that is too accurate?

And based on that you conclude that what??? I'm a back yard plinker?

I've been shooting F Class since long before they heard of it in the USA, but you are correct, I don't shoot bench rest, sorry but I find it boring. No disrespect to those that enjoy the sport.

As for your assessment of the accuracy of the FX120, sorry but you are in dream land. At best it is plus or minus 0.03 rounded to even numbers which makes it plus or minus 0.04. It only displays even numbers. That's almost a tenth of a grain, in the real world. Add to that voltage fluctuations, the crappy load cell sensor etc. Hey, it's a nice value scale that's greatest value is the auto trickler, but it aint no analytical balance by any means.

At least be honest about it.

this is your problem in reading specs and understanding them\
once again you are wrong...

a fclass target is SEVEN times the area of a br 1000 yard target...not reqally precsion at all..IMHO.

 

[RegionRat]

Edit. I've just reread PracticalTactical's last post and wonder whether the ± .04 gr. he mentions for the .02-gr. readability scale means that, in a large group of weighed charges--all weighed to 31.0 gr.--the spread might be something like 30.96 gr. to 31.04 gr. So first, do I have this right? And second, is this much variation likely to manifest itself in noticeable velocity variation? Obviously for light charges in the 20-30-gr. range, the effect will be greater than with heavier charges in the 50-60-gr. range.

The way we describe the risk that a scale tells the "truth", is called uncertainty.

The uncertainty is often at least as big as plus and minus the resolution and often more.

ETA: here ya go, some nightstand reading to get you all onto the same page with scales and the terminology of their performance and calibration.
https://nvlpubs.nist.gov/nistpubs/Legacy/IR/nistir6855.pdf

Like I said earlier, the thread is going astray from the original question of what is good enough to sort cases...

 

[DocCarbon]

Great detail, DocCarbon. If I'm reading all of this correctly, I'm coming around to thinking that a scale good for .001 gram (.02 gn.) resolution (like the FX-120i) should be sufficiently precise for weighing cases and powder, although that was my original question. Is there any practical reason for any more precision for cases and powder? With this level of precision, I'm guessing that a group of, say, 10 cartridges all charged to the same weight of powder might, in fact, differ by up to about .06 gr. of powder. So when you charge your 6PPC cases with your .001 g. scale set to 31.0 gr., you might end up with the lightest charge being 30.97 gn. and the heaviest, 31.03 gr. I'm guessing that this level of charge-weight difference would not be accompanied by any discernible velocity differences. But do I have this right?

However, as PracticalTactical has noted, this level of precision would be completely inadequate for weighing primers. For this, I'm assuming that you would have to go to the .0001 gram (.002 gn.) scales. Unfortunately, this gets you into pretty pricey territory. Is there a .1 mg. scale that is as affordable as the FX-120i?

I can honestly tell any of you , 50 years ago when I batched for Hercules industrial dynamite division and later on for smokeless powder division . There was 3% +,- error allowances . So Today ? who the hell knows with powders being manufactured nearly anywhere but here and as fast as the Yankee Bucks can flow .

MY simple answer is ; What difference does it make weighing a primer ?. Would you be able to decipher the difference in mixture or cup weight . NO !. Primers are held at tighter tolerance perhaps 1-1.5% .

I've personally shot #2 of MY BEST groups with SD in excess of 100 Fps . Granted NOT in BR ,as I NO longer own anything resembling a BR Rifle . Yet groups at 200-500 meters were covered by dimes and quarters .
MY standard group shooting consist of #3 groups #5 Each one fouler ,so 16 Shots first called fouler .

IF and old slug like ME can do that with AR platforms ,for total out of pocket expenses say under $2K ,I'd shutter to think what BR shooters are capable of .

I bought a New Savage LH .308 Years ago ,popped a Decent Nikon on it ,cleaned the bore shot cleaned after each shot ladder stepping 1 clean ,2 clean ,-10 rounds . Cleaned it and fired #2 hand loads , the bullets went through the same exact hole , several people on the line witnessed that ,as back drops or Proofer's confirmed it . I then like a dumbass adjusted the scope for wind . I cleaned it and put it in My safe .

There are so many uncontrollable factors ,which are beyond ANY shooters ability what can you do but the best with what you have to work with . #5 grains of powder in your next round ,have less graphite coating than your previous round . Hope you can see where I'm going with this .

 

[Lbart]

this is your problem in reading specs and understanding them\
once again you are wrong...

a fclass target is SEVEN times the area of a br 1000 yard target...not reqally precsion at all..IMHO.

6bra1k, having set national records in both 1k BR & F-Class I think I can comment on BR vs FC.

I must point out the BR target has a 3” X-ring and a 7” ten ring, while the F-Class has a 5” X-ring & 10” ten ring. The FC target rings are only roughly twice the area of the BR, if at my age my math is correct.

Even so, the FC shooter has to wait for the target to be pulled, marked, and scored (while the conditions change) before he can shoot another shot, while the BR shooter can continue to send bullets downrange as fast as he cares to. Also, the FC’er has to send 2 to 3 times (15-20 vs. 5-10) as many shots into his target compared to a BR shooter.

At the TX State Championships last weekend, the Champion Tim Vaught shot a 994-55x out of 1,000-100x. That means only 6 shots were out of the 10” ten rings & 55% were in the 5” X-ring. This shooting was over a 2-day period, shooting, 3 strings on Sat & 2 on Sun and doing target pulling duty between strings. Believe me, the wind & mirage were changing all the time. Don’t tell me equal precision is not required in F-Class!