Scale accuracy and precision, how much is needed?

[hounddawg]

Long range shooters have their work cut out for them.

long range gets complicated

In F class and Palma you shoot 20 round groups that need to be centered. I use CEP (circular error of probability) in addition to group size and velocity SD to decide on loads

In Precision shooting you only have to hit the target once but from unknown ranges out to 1000 yards

In long range benchrest they want tiny groups of five shots

different guns, different cartridges used, different round counts.

I have not spent a lot on my scales but they give me repeatable results I am happy. I use a pulled .22 40 gn bullet as a checkweight. I weighed it when I pulled it and weigh it before ever load session. My $20 and $200 scales repeat within .002 either way. My acccurized beam agrees with the electronics, that's all I ask

[higgite]

Originally Posted by hounddawg

My $20 and $200 scales repeat within .002 either way.

That's .002 grams, not grains, right?

[hounddawg]

That's .002 grams, not grains, right?

yep. My scales measure to .001 milligrams and .01 grains. Looks like the repeat ability is around plus or minus .002 grams and .01 grains. I like to develop my loads where I have a node where there is some leeway on either side and I also load to the distance I am shooting. I develop on the gram scale and am real picky about the charge. When I find a good node I just use the grain scale and call anything good that is plus or minus .02 grains for 300 and 600. At 800 I go back to being anal.

Sort of off topic but still in the cheap scale category. Be aware that anything that uses the 123 gram load cells is real picky about cold weather. If my Tree123 is below 60F it goes spastic, real spastic.

I keep banging on that $20 Smartweigh but it seems to be a much better scale quality wise. For 2- 3 months now has been as repeatable a scale as I have ever owned. I have a little .22LR bullet I pulled a while back. It weighed 39.96 grains on that scale the first day I weighed it and has never been off that reading more than .01 grains in either direction since whether it was 45F in the shop or 70F

[jugornot]

Seems to be some misinformation here. A scale that measures 0.001 grams is only accurate to 0.02 grains. For it to be accurate to .01 grain it would have to read 0.0006479891 grams. The problem with a load cell scale is that it runs a program in the background that tries to keep drift to a minimum. That program does not do so well with slowly adding weight. The scale gets confused adding powder 1 grain at a time. it doesn't know if it is a change in weight or a change in drift. Load cell scales do much better when adding a large weight all at once and can be very accurate. It is the nature of a load cell scale. Their has been no innovation that gets past this limit of load cells.
Video
I wish there was a way to be as accurate as more expensive scales (while trickling,) but there isn't. I have spent money on many scales of the cheaper variety. They all have problems. Are they accurate? Yes to a certain degree. For weighing bullets or brass I have no problem with them. They are very handy mostly because of a lack of breeze screen.
Finally is this accuracy necessary. The Prometheus and FX120i more likely appeal to my ocd. Well not the Prometheus, I am cognizant of budgetary considerations. But for the most part it is unnecessary. Do your load development find a velocity node and you are golden with about anything out there. You may achieve smaller SDs with the better scales, but that has little affect on accuracy. The truth is many things affect accuracy. I hold my charges to plus or minus 0.02 grains. I anneal every time I reload. I trim every time. I check concentricity. Does this affect accuracy? Yes because it affects my confidence and that affects my accuracy. Good ammo doesn't always get the win. How much does it matter? According to this 3%. If you throw in Tighter groups and hotter loads 9%. If you are trading up from steel Russian ammo maybe a bit more.

[hounddawg]

Jugornaut I have never said that these inexpensive scales were accurate to within .001 grams. I have no clue what the accuracy is since I do not own certified check weights nor do I own a certified scale to check them against

On the precision side they seem to be precise to plus or minus .001 grams or the same as a A&D FX-120i. That would be a 3 milligram range which would be .04 grain. If you want finer resolution than that then you have to go to a balance that reads to .0001 such as a Sartorius. As long as they are precise I could don't worry about accuracy. Non certified check weights are good enough for reloading purposes to check accuracy. I worry more about precision and repeat ability

The tradeoffs are obvious. A scale that uses magnetic restoration will be faster and more responsive and also much more expensive.

For my inexpensive scales to ensure that I am getting readings accurate to within a kernel or two I will take the pan off and replace it to double check the weight, sometimes multiple times. Still between throwing my initial charge I can do 20 -25 rounds every fifteen minutes using a throw for initial charge, and fingers to trickle. These little units have really good results on the repeatability

edit- in this test - http://forum.accurateshooter.com/thr...ility.3961911/

I found the repeat ability within .02 to .04 ES when weighing bullets which is what I originally bought he scale for.


The is the subject of the discussion, are the high dollar scales necessary. How much better would my numbers be than what I am getting with my $20 scale

https://thefiringline.com/forums/att...8&d=1545151512

https://thefiringline.com/forums/att...7&d=1545151399

https://thefiringline.com/forums/att...5&d=1548183714

If you develop your load correctly you should be able to be within plus or minus a full .1 or .2 grains of powder and it should be accurate to over 800 yards

[jugornot]

Even lifting the pan you must make sure your weight without the pan remains the same. If it drifts you must rezero or accept additional inconsistencies. I was an instrument tech for 40 years. I worked with scales of every size and type. I also said just about everything out there would work. Even using volume works. That is how powder drops work. As I said everything works. You seem to be saying a $20 scale is as good as a $500 scale and it just isn't so.I have both and they are nowhere near equal.

[hounddawg]

As I said everything works. You seem to be saying a $20 scale is as good as a $500 scale and it just isn't so.I have both and they are nowhere near equal

I beg to differ, I pointed out the negatives of inexpensive scales several times in this and my other threads on scales.

Read the title. Scale accuracy and precision, how much is needed? How much money do we need to spend? Most of us produce decent ammo for our needs with everything from powder throws and beam scales to sub $100 Chinese electronics. Thousands of rounds will be shot this weekend weighed out on automated powder throws from Hornady, RCBS and others as well as other reloadiing scales with a resolution of only .1 grain. People will be happy with how those reloads perform too

Just wondering how many shooters on here that really need the precision of or can take advantage of the accuracy and precision of the high dollar scales. The people I talk to at the range and at matches are using everything from low dollar reloading scales like me to $2K Sartorius autothrow setups with all the Area 419 bling. One thing I have noticed is it all boils down to who can keep them closest to the center and that changes match to match and relay to relay.

I have seen factory ammo shoot 199's and clean 200's when the shooter knew what he was doing and the finest hand loads shoot in the 180's when the shooter was just having a bad day. It can change from relay to relay

[pete2]

Check weights are your friend. I use them on my balance scale and the electric one.
Once my measure is dialed in (whether Dillon or UniFlo) they usually stay right on. This with ball powder or fine grained powder like Bullseye. Unique will vary, + or - a tenth or 2, still some pretty accurate 9 MM loads with Unique.

[jugornot]

Originally Posted by hounddawg

yep. My scales measure to .001 milligrams and .01 grains.

This is the misinformation I was talking about. .001 milligrams is .000001 grams. Also the .001 gram scale is only accurate to .02 grains. I have both a Myweigh and a Smartweigh and a couple of other scales that are load cell scales. On all of them I can trickle over .1 grain without them reacting. It turns out that you throw low trickle fast and wait a few seconds. Trickle a few kernals, lift pan wait for it to settle. Repeat ad nauseam until possibly it is over and you tweeze out a grain. Varget is easy. I could hear the grains hit the pan and get very close. 4350 should be similar. 223 CFE was much harder. It would be better if you zeroed your scale every time you lifted your charge.

Try this. Zero your scale. Drop a grain of 4350. I bet your scale is still zero. Wait a few seconds drop another grain. Still zero. This is where load cell scales are lacking. The drift compensation routine is very aggressive. I have 2 load cell scales that have wall warts and do not turn off. They drift by whole grains over time. I zero my scale possibly every 30 minutes and it is usually a grain of powder on the scale somewhere.

So we come to the to the original topic. Does it matter? I can say my SDs are lower than yours. According to my references it makes 3% difference. I paid about $1000 (for the complete autotrickler setup) for that 3%. I think it was worth it.

[hounddawg]

This is the misinformation I was talking about. .001 milligrams is .000001 grams.

I made a typo and typed milligrams instead of grams, call the grammer police and lock me up

Drop a grain of 4350. I bet your scale is still zero. Wait a few seconds drop another grain. Still zero. This is where load cell scales are lacking.

Once again this is not a thread to say that $20 dollar scales are as accurate as $750 dollar scales. Several posts ago I acknoledged that a $750 dollar A&D is a far superior scale to anything I own and if I were compounding pharmaceuticals or something that needed to be super precise I sure as heck would not be using a Smartweigh

the question is do you need to spend $750 on a reloading scale to get consistent muzzle velocities. I say no

I have pages of spread sheets on chrono results, with single digit SD's sometimes covering several tenths of a grain. These charges were weighed on everything from a RCBS 750 Chargemaster, a beam scale and a couple of Amazon specials. Now I can either buy a high dollar scale for internet bragging rights or just keep loading ammo with regular old scales and still get single digit results on my velocity SD's

hamburger made from sacred cows is the best

[jugornot]

Originally Posted by hounddawg

I made a typo and typed milligrams instead of grams, call the grammer police and lock me up



Once again this is not a thread to say that $20 dollar scales are as accurate as $750 dollar scales. Several posts ago I acknoledged that a $750 dollar A&D is a far superior scale to anything I own and if I were compounding pharmaceuticals or something that needed to be super precise I sure as heck would not be using a Smartweigh

the question is do you need to spend $750 on a reloading scale to get consistent muzzle velocities. I say no

I have pages of spread sheets on chrono results, with single digit SD's sometimes covering several tenths of a grain. These charges were weighed on everything from a RCBS 750 Chargemaster, a beam scale and a couple of Amazon specials. Now I can either buy a high dollar scale for internet bragging rights or just keep loading ammo with regular old scales and still get single digit results on my velocity SD's

hamburger made from sacred cows is the best

You also misstated that your scale was measurable to .01 grain.

The entire purpose of the lifting the scale scenario was to show that load cell scales are not suitable to trickling. And someone that doesn't know this will throw some outrageous powder charges. Are there work arounds? Yes. But it takes tremendous patience to throw repeatable charges with a cheap electronic scale. I know. I did it. As I said everything will work. Using dippers will work. I think $900 for a statistical 3% gain is worth it. By the way the auto trickler - auto throw is a complete automatic dispenser. I have a Lyman gen 5 powder dispenser and it was $300. It was accurate within plus or minus .1 grain. I wanted better. The auto trickler is only at least twice as good and costs 3 times as much. The trickler-throw with scale is $900. And as far as internet bragging, it is no less of a brag to say you throw repeatable powder charges with a $20 scale, when that scale is unsuited to trickling.

Here
and
Here
and
Here is a description of the differences most notably: "In today’s industry, two weighing cell technologies are predominately used. They are strain gauge and electromagnetic force compensation (MonoBloc) technology. MonoBloc weighing technology ensures the highest level of counting accuracy and repeatability for reliable results. Generally, MonoBloc load cells are ten times more accurate than standard load cells with strain gauges."
And
"Downsides include limited resolution and limited accuracy. Thus, strain gauge technology isn’t useful for all situations."

Once again you are recommending a scale that is intrinsically unsuited for the task for which you recommended. If a neophyte takes your advice without understanding the problems and work arounds then they could have serious consequences. I ask you throw a charge using your methods and write down every move and step. If honest you will have anywhere from a long paragraph to close to a page of description. The proper use of a strain gauge scale would be to check the weight of a thrown charge. Checking the weight of a charge is the most accurate use of such a scale. As for me and my cheap digital scale I ended up throwing as close as I could and counting grains to get the consistency I wanted. I shoot a lot and my time was worth the cost of the auto-trickler. I think a good accurate throw with the electronic scale as a check scale would be better than trying to trickle with the thing. I think you could throw 3 or 4 times to get your charge before you could trickle the charge accurately once. I see a very good thrower with a cheap electronic scale for checking as a better method than trickling on a cheap scale. Remember the Harrels throw had lowest group in one test. Now thanks to you and your advice the Prometheus manufacturer will go broke shortly. I can hear the people falling off the waiting list now. But seriously if there is a waiting list for leasing a $4300 leased dispenser, I think the Auto-trickler a bargain. You don't.

[hounddawg]

dozens of posts now jugornaut and you still have not answered the basic question

If people can get single digit velocities from their rifles consistently with inexpensive scales why buy a expensive one?

You do have a great sales pitch worked up though if you ever want to go into marketing expensive scales

slam my equipment all you want but I get great results at the shooting bench over the chrono even without bragging rights to a high end scale. Now if I can just get those groups centered.

[jugornot]

I have informed this group of the problems of trickling with a cheap digital scale. Nothing more or less. If I hurt your feelings I apologize. The equipment you use has a definite value for reloading. I thought I had made that clear over and over. Its only drawback is trickling. I used similar equipment intimately. Perhaps in this thread about scales, I was wrong to throw in a dispenser. I apologize to the group.
But my caveat about trickling on a cheap scale stands.

P.S. Facts generally are the best sales pitch.

P.P.S. If you read carefully Here the shooter is much more the reason of accuracy than the equipment for a given cartridge.

[hounddawg]

why would my feelings be hurt?

I changed over from using a beam three months ago to that electronic and weighing all my match rounds on it has me shooting low to upper 190's consistently. That's 20 shot relays at 300 to 800 yards, not 5 shots at 100 yards. My dropped points are not due to vertical flyers but with wind related 9's on the horizontal and overall group centering not the best. If I were getting random vertical flyers I would suspect the ammo but it seems my wind and mirage reading is the fault

My feelings would have been hurt if I had spent two grand on a weighing setup and discovered I did not need that much precision and accuracy on my charges to get good results

[jugornot]

Originally Posted by hounddawg

slam my equipment all you want

You seem hurt that I mentioned a weakness of your equipment. You constantly mention the weakness of my equipment. Its cost. If you peruse this page we are as evenly divided as the pros are. The article states the groups are evenly distributed except the top 4. They all used high end scales. As these are pros one can hardly question their motivation. I don't question yours. I endorsed throwing a charge and measuring on a cheap scale. This is their best use. Trickling with a cheap scale can be problematic. This is my claim in this thread. As far as the answer to your question are they necessary, at least half of the top 100 PRN shooters think they are necessary.

[hounddawg]

You seem hurt that I mentioned a weakness of your equipment

still don't get it do you, the point is not how good the scale is or is not. It's all about the results you get with the scale at the firing line

here is a spreadsheet from a recent load development. Eight groups of five shots. Well 38 shots made it onto the chrono, two did not because of user error. Two groups had SD's less than 5. Five groups had single digit SDs. Thirty eight rounds chrono'ed with one outlier which could be chrono error, all weighed on a $20 scale.

The scales accuracy or lack thereof had little to do with these results. It takes the right combo of powder choice, load weight, primer, bullet and seating depth.Once you find the right combo you can throw the rounds on a Promethius or a RCBS Chargemaster and get the same results at the shooting bench. If scale accuracy and precision was the only thing needed for consistent velocity you could use a .0001 gram scale and a fine grained powder and get SD's of zero with any charge weight you picked every single time. But we all know that doesn't happen, even for the guys with .0001 gram scales using ball powder

[JohnKSa]

You are obviously talking past each other--I can't tell if it's intentional or not, but either way, this is going nowhere.