Getting single kernel precision cheap!

[dannyjbiggs]

Have you ever tuned up a mechanical reloading scale that was made by Ohaus, so that it comes to the same exact zero point no matter how you put the pan on, or used one in conjunction with a web cam to eliminate parallax and magnify the pointer and scale? My scale is a lot more sensitive and repeatable than when it came out of the box the first time, and I am not so much concerned with its absolute accuracy as long as it repeats well when weighing the same weight. can mechanical things be modified to work better than when they were new? Absolutely!

Are you referring to an RCBS 304 scale?

 

[JFrank]

I may agree they were loaded the same.
BUT
YOU do not know what the load was

NOR
can you repeat the load.
end of discussion.

that is not "single kernel" accuracy, it is still plus or minus 0.1.
design accuracy of the beam and the lite

This is pretty interesting...

The pan base self centers my pan, but I checked this several times (maybe 5 ish) when I was first setting this up by lifting the pan all the way off and replacing it to make sure the beam repeated. With my magnifying glass I can see the wobble of the pan in the needle until it comes to a complete rest and the same weight returned to the same equilibrium across the several times I tried it before proceeding.

Out of curiosity, Boyd, how would you recommend I go about further improving this beam? I'm nervous about stoning the knife edge, as I feel like getting the two knives off from each other would be more detrimental than any increase in their current finish. Are there other tricks I can try?

I’m not speaking for Boyd but if you search you’ll see several threads on beam scale tuning and maintenance.
BTW - I wouldn’t start by sharpening the knifes.
J

 

[Bc'z]

This is pretty interesting...



Hemorrhoidal flare up!!

 

[Ccrider]

We may just have to disagree, but in case this is simply us not understanding each other, I'll try to explain myself differently:

Gravity, a fine knife edge beam and a smooth bearing surface, and a sufficiently fine indicator of equilibrium do not have the limitations that electronic scales do for comparative analysis. I didn't set my beam to 30.0gns and then measure up to equilibrium. I had the Chargemaster throw a charge and then set the beam to equilibrate with that charge. I don't care if it was actually 30.04 or 29.97gns, I set it to equilibrate with that first charge. Every charge after was then made the same as that first charge by adding or removing single kernels to reach the same equilibrium.

EDIT: I'll add that if you said, ok now go load 10 more today at the exact same charge weight, I wouldn't be able to. I took the setup apart. But in that reloading session, those are loaded the same.

Why not save that first charge as your test weight? That way, you start at the same weight each day.

 

[jepp2]

With my magnifying glass, I could easily resolve a single kernel up or down

I have been on a quest to improve the accuracy of my powder charges. Not quite ready to drop the $$ for the high end system. My steps include:

- I have 2 RCBS Chargemaster 1500 to work with. I would set the throw 0.1 gr light, transfer into my beam scale pan and trickle until the beam balanced. I could see the movement from a single granule of powder. HOWEVER, after the scale balanced, I would lightly touch the pan (up a small amount, then down a small amount) and the scale would not return to the -0 position. For the movement up, it would return short of coming to -0 after it was under the -0 mark. And the reverse for the other movement. I attributed it to the friction of the knife edges. Tried it on two different beam scales, similar result.

Then I watched the Eric Cortina video where he had an alternate method to try to attain improved accuracy from his Chargemaster. He had a scale that would provide accurate measurement to assess his improvement.
https://bulletin.accurateshooter.com/2015/05/cortinas-corner-chargemaster-tips-the-trickle-test/

My trickler "sucked" anyway, so I got the Dandy trickler he was using. Wow what an improvement. No more removing powder granules with tweezers. And since I had two Chargemasters, I throw 0.2 gr. light on the first one and transfer to the second one. First thing I learned is how bad the dispensed charge accuracy is from a Chargemaster. Now is my first scale reading correct, or the second? I am looking for consistency, not absolute. So by slowly adding granules and waiting for the second to read, I feel I have achieved improvement. My ES and SD are less. And I can fill cases at the same speed as I did before using just one scale.

Once your scale balances, I would be interested in you making the beam move the small amount I did, and see if yours balances on -0 again. I would have it move up (or down) enough so the pointer went about 2 graduations above (or below) the -0, but would not come up to the -0 from below. Not 3 swings, just 2.

 

[INTJ]

When I got my Sartorius Entris 128 (.001 grains resolution) I tested my RCBS 10-10. I had used the 10-10 for 1K BR several years ago and I wanted to know ho accurate it was. So I loaded up five charges on the 10-10 and made sure the pointers were exactly aligned for each charge. Even with that, there was almost .1 grains of variation across those five charges.

Now a tenth of a grain in a 300 WSM BR rifle isn't significant. I doubt it would matter in a .308. However with my 6 BRA BR rifle it does matter. Using the Sartorius one day I loaded and shot several 5-shot groups that were separated by .1 grain in charge weight, and the velocities consistently increased by a few FPS for each load.

So while an manual scale is better than the RCBS Chargemaster, a manual scale is not close to a good precision scale and a low end electronic scale is worse. I am sure Scott Parker can get a manual scale to be much closer to a precision scale, but it still won't be as fast or as accurate as the AutoThrow/AutoTrickler on a Sartorius.

Then again, outside of LR BR with small capacity cases in good conditions, it likely won't matter.

 

[Straightshooter1]

I have been on a quest to improve the accuracy of my powder charges. Not quite ready to drop the $$ for the high end system. My steps include:

- I have 2 RCBS Chargemaster 1500 to work with. I would set the throw 0.1 gr light, transfer into my beam scale pan and trickle until the beam balanced. I could see the movement from a single granule of powder on my computer screen. HOWEVER, after the scale balanced, I would lightly touch the pan (up a small amount, then down a small amount) and the scale would not return to the -0 position. For the movement up, it would return short of coming to -0 after it was under the -0 mark. And the reverse for the other movement. I attributed it to the friction of the knife edges. Tried it on two different beam scales, similar result.

Then I watched the Eric Cortina video where he had an alternate method to try to attain improved accuracy from his Chargemaster. He had a scale that would provide accurate measurement to assess his improvement.
https://bulletin.accurateshooter.com/2015/05/cortinas-corner-chargemaster-tips-the-trickle-test/

My trickler "sucked" anyway, so I got the Dandy trickler he was using. Wow what an improvement. No more removing powder granules with tweezers. And since I had two Chargemasters, I throw 0.2 gr. light on the first one and transfer to the second one. First thing I learned is how bad the dispensed charge accuracy is from a Chargemaster. Now is my first scale reading correct, or the second? I am looking for consistency, not absolute. So by slowly adding granules and waiting for the second to read, I feel I have achieved improvement. My ES and SD are less. And I can fill cases at the same speed as I did before using just one scale.

Once your scale balances, I would be interested in you making the beam move the small amount I did, and see if yours balances on -0 again. I would have it move up (or down) enough so the pointer went about 2 graduations above (or below) the -0, but would not come up to the -0 from below. Not 3 swings, just 2.

I found this same kind of issue with my RCBS M500 balance beam scale. I use my scale with a webcam focused close up so that there's no parallax issue AND I can easily see the difference a granule will make (whether it's ball or extruded). Trying to get that precise consistency was/is difficult for the scale, but I found it's doable. After a lot of experimentation and checking and comparing to see how I could get the most out of this scale I found a technique that has worked quite well for me. What I do is make sure that when I place the pan and get ready to release it to get the measurement, I need to make sure I release it from exactly the same position (what's I'd call the starting point) so the the oscillation of the arm is always the same. It's not only the vertical point of release but also being sure my starting pint is where the arm is not more forward or back so there's no change in the way the knife edges sit in their groove. If I happen to jar the scale, I find I usually need to find a new starting point. This has worked quite well for me.

Also, when I throw the powder, it's only a few a few granules off so that when I trickle up, it doesn't take much to get what I want. I've put a clear plastic straw over the end of my trickler that extends about 1" and put an old plastic card under the base of the trickler to give it a little tilt. So I typically don't turn it to trickle, but simply tap it to in effect vibrate the granules down and I can see them make their way down the plastic straw and can drop just one or two or whatever as needed. If I need more faster, I simply get a little more aggressive with my tapping.

 

[Evan]

I'd ask a different question: how much powder measuring precision is enough to where it's not limiting your accuracy potential?

I am looking to turn the 0.6" groups at 300yards with my 22BR more consistently into the 0.3" groups I get on occasion.

Once your scale balances, I would be interested in you making the beam move the small amount I did, and see if yours balances on -0 again. I would have it move up (or down) enough so the pointer went about 2 graduations above (or below) the -0, but would not come up to the -0 from below. Not 3 swings, just 2.

Part of my routine is I drop a kernel (or pull one out) and ever so lightly bump the pan tray up with my tweezers, enough to swing the scale an 1/8" or so and let it come back to equilibrium. Doing this, it appears to more repeatably return to equilibrium. If you just drop kernels in and nothing else, you might get a couple kernels in the pan before the needle moves on its own.

 

[bozo699]

When I got my Sartorius Entris 128 (.001 grains resolution) I tested my RCBS 10-10. I had used the 10-10 for 1K BR several years ago and I wanted to know ho accurate it was. So I loaded up five charges on the 10-10 and made sure the pointers were exactly aligned for each charge. Even with that, there was almost .1 grains of variation across those five charges.

Now a tenth of a grain in a 300 WSM BR rifle isn't significant. I doubt it would matter in a .308. However with my 6 BRA BR rifle it does matter. Using the Sartorius one day I loaded and shot several 5-shot groups that were separated by .1 grain in charge weight, and the velocities consistently increased by a few FPS for each load.

So while an manual scale is better than the RCBS Chargemaster, a manual scale is not close to a good precision scale and a low end electronic scale is worse. I am sure Scott Parker can get a manual scale to be much closer to a precision scale, but it still won't be as fast or as accurate as the AutoThrow/AutoTrickler on a Sartorius.

Then again, outside of LR BR with small capacity cases in good conditions, it likely won't matter.

100% my findings almost to a T!
Wayne

 

[Evan]

Why not save that first charge as your test weight? That way, you start at the same weight each day.

It's largely because I don't care exactly what the true value is or hitting it right on in the future. My node is wider than this tolerance, so if this box is 30.04 and then next is 30.01 and the next is 29.96, I don't think it will matter (as far as I know). I just want each string of 5 to be closer to identical so that maybe the groups tighten up a little. And in my usual fashion: if the groups don't improve, I will ditch this and go back to just the chargemaster. My modus operandi is that everything has to earn its way into my reloading routine.

When I got my Sartorius Entris 128 (.001 grains resolution) I tested my RCBS 10-10. I had used the 10-10 for 1K BR several years ago and I wanted to know ho accurate it was. So I loaded up five charges on the 10-10 and made sure the pointers were exactly aligned for each charge. Even with that, there was almost .1 grains of variation across those five charges.

I'm interested in figuring this out, because what you experienced could be happening to me: my old budget balance beam may not be providing better consistency, but it sure feels like it is. A proper scale like a FX or Sartorius is in my future but current events have just delayed it some until the household income consistency is restored. Until then I'm stuck reading the target (providing this stay at home order is lifted and I can go shooting to have targets to read).

 

[Hohn]

I am looking to turn the 0.6" groups at 300yards with my 22BR more consistently into the 0.3" groups I get on occasion.

And what data suggest that it is powder metering precision that is preventing you from 0.3"?

From Mark Gordon Comment on a recent PRB article:

"So my current position is that at the ranges we tested (600 yards) low extreme spreads in velocity is not nearly as important as some would think. I ran a 6.5 Creedmoor charge weight ladder test AFTER I established that the 147 ELD-M bullets wanted to be at .085″ jump and the first 14 shots out of 15 total were under 1/2 MOA even though there was a 137 FPS extreme spread in the velocity. We see it all the time where we see very large extreme spreads in velocity, while having below 1/2 MOA vertical in impacts."

I'm not to sure powder weight as nearly as critical as some believe it to be. Factory hornady match ammo has capacity all over the place and can vary charge weights by as much as 0.5gr yet still hold half moa vertical at 600y.

Hmm.

https://precisionrifleblog.com/2020/03/29/bullet-jump-load-development/

 

[redrockranger]

I haven't ever encountered a viable node that was only 0.1, or even 0.2gns wide. I have seen compelling evidence that having all rounds in a group at the same charge weight (down to the kernel) is beneficial, thus why I presented this as an option to folks who maybe, like me, wanted to increase the consistency of their charge weights without spending much money (free for me, as I've had this beam around for a few decades now collecting dust).

I never had a Charge Master or similar. First digital was a simple Pact scale, next was a RCBS 750 digital scale . Both were a pain in the ass. Drifted after a few measurements. Drug out my old RCBS 505 beam and no more problems. Use it with my battery powered Midway trickler.

How many serious competitive shooters that use your method ? How many trophies have you got on the mantle ? How many Hall of Fame points have you.

When i was a young man i could shoot a custom rifle and could tell if it was a button or a cut rifled barrel.

 

[Evan]

And what data suggest that it is powder metering precision that is preventing you from 0.3"?

From Mark Gordon Comment on a recent PRB article:

"So my current position is that at the ranges we tested (600 yards) low extreme spreads in velocity is not nearly as important as some would think. I ran a 6.5 Creedmoor charge weight ladder test AFTER I established that the 147 ELD-M bullets wanted to be at .085″ jump and the first 14 shots out of 15 total were under 1/2 MOA even though there was a 137 FPS extreme spread in the velocity. We see it all the time where we see very large extreme spreads in velocity, while having below 1/2 MOA vertical in impacts."

I'm not to sure powder weight as nearly as critical as some believe it to be. Factory hornady match ammo has capacity all over the place and can vary charge weights by as much as 0.5gr yet still hold half moa vertical at 600y.

Hmm.

https://precisionrifleblog.com/2020/03/29/bullet-jump-load-development/

With respect to Cal and his more rigorous statistical approach to answering questions (which i appreciate), I'm talking about going from 0.3MOA down to 0.1MOA for benchrest shooting which is a much different goal than achieving competitive PRS accuracy - the focus of all of his articles.

I am getting maybe 2 in 10 groups that measure 0.3" (at 300 yards, my current development distance where I can resolve bullet holes in all conditions) and the rest are between 0.6" up to 1". I have no data suggesting powder metering is the problem (I don't use a chronograph, and have yet to be convinced that ES or SD have much of any effect on actual accuracy), but charge weights are something that can be measured and eliminated from the variables present. After this, I'll have to dive into the anal retentive art of weighing primers and sorting bullets, because those are the three remaining rocks I've left unturned to date.

 

[INTJ]

Evan says he wants to shoot .3" groups at 300 yds. I don't think you can get there consistently without doing the micro tuning WHILE shooting that short range BR guys do. Also, he will need lots of wind flags. After all, NBRSA Official Screamer Groups at 300 yds are 5 shots under .450" and .3" is well under that. A short range BR shooter can show the way.

For long range need to look to LR BR to find out what loading techniques produce the best results. PRS doesn't require BR level accuracy--other things are more important in PRS.

I sometimes get to tune at 600 or 1000 yds and when I do I don't use a chronograph. Groups size is all that matters. However, most of my load development is done at 200 yds and at short range velocity spreads are an important indicator. That said, I will always pick groups size over velocity spread, and I have seen .25" 5-shot groups at 200 yds that have ES in the high teens. I have never seen a good group at 200 with more than 20 fps ES.

Now if I only needed 1/2 MOA at 600 or 1000 yds I wouldn't worry about measuring to the kernel. And I don't worry about that level of measuring precision for my non BR rifles.

The level of accuracy needed, distance, and format determine what is most important in each shooting discipline. It sounds to me like Evan wants top BR level accuracy.

 

[Albany Mountain]

This is my magnifying glass on my Lyman scale.

 

[Evan]

Evan says he wants to shoot .3" groups at 300 yds. I don't think you can get there consistently without doing the micro tuning WHILE shooting that short range BR guys do. Also, he will need lots of wind flags. After all, NBRSA Official Screamer Groups at 300 yds are 5 shots under .450" and .3" is well under that. A short range BR shooter can show the way.

For long range need to look to LR BR to find out what loading techniques produce the best results. PRS doesn't require BR level accuracy--other things are more important in PRS.

I sometimes get to tune at 600 or 1000 yds and when I do I don't use a chronograph. Groups size is all that matters. However, most of my load development is done at 200 yds and at short range velocity spreads are an important indicator. That said, I will always pick groups size over velocity spread, and I have seen .25" 5-shot groups at 200 yds that have ES in the high teens. I have never seen a good group at 200 with more than 20 fps ES.

Now if I only needed 1/2 MOA at 600 or 1000 yds I wouldn't worry about measuring to the kernel. And I don't worry about that level of measuring precision for my non BR rifles.

The level of accuracy needed, distance, and format determine what is most important in each shooting discipline. It sounds to me like Evan wants top BR level accuracy.

I have shot a few 600 and 1000yard comps at CRC. I'm looking to get into that a lot more. I like to tune at 300 because I can see my bullet holes reliably, which allows me to develop and improve what I'm doing in real-time. At 600 and beyond, where I shoot, I have to walk to the target, you can't drive. With a 20-30minute round-trip walk, it's not so convenient to go check your target after every couple groups to make changes and improve what you're doing.

I believe that I am at that tipping point. I use wind flags, I use premium components in custom rifles, I shoot (until COVID) 50-100 rnds of careful practice every weekend; I've covered all the basics and I've settled into a consistent level of performance that I'm trying to break out of to start shrinking the groups down again.

 

[TimS]

if you have it down to a single kernel, just count the kernels and make them all the same. Something to do during this lockdown.

 

[Straightshooter1]

if you have it down to a single kernel, just count the kernels and make them all the same. Something to do during this lockdown.

But first, you'll have to sort them by size.

 

[INTJ]

I have shot a few 600 and 1000yard comps at CRC. I'm looking to get into that a lot more. I like to tune at 300 because I can see my bullet holes reliably, which allows me to develop and improve what I'm doing in real-time. At 600 and beyond, where I shoot, I have to walk to the target, you can't drive. With a 20-30minute round-trip walk, it's not so convenient to go check your target after every couple groups to make changes and improve what you're doing.

I believe that I am at that tipping point. I use wind flags, I use premium components in custom rifles, I shoot (until COVID) 50-100 rnds of careful practice every weekend; I've covered all the basics and I've settled into a consistent level of performance that I'm trying to break out of to start shrinking the groups down again.

300 yds is a good distance to work up loads, but consistent .3" 5-shot groups aren't realistic at 300 if you are shooting a long range rifle. It takes a short range rifle to do that. It's truly that specialized.

My experience is a long range BR rifle needs to shoot around .3" at 200 yds if it is a 6BRA and around .5" at 200 if it is a 300 WSM. Both will shoot similar groups at 1000 yds with the 6BRA doing better in good conditions, the 300 WSM doing better in poor conditions, and its a toss up in average conditions.

What kind of long range competition are you shooting?

 

[Evan]

300 yds is a good distance to work up loads, but consistent .3" 5-shot groups aren't realistic at 300 if you are shooting a long range rifle. It takes a short range rifle to do that. It's truly that specialized.

My experience is a long range BR rifle needs to shoot around .3" at 200 yds if it is a 6BRA and around .5" at 200 if it is a 300 WSM. Both will shoot similar groups at 1000 yds with the 6BRA doing better in good conditions, the 300 WSM doing better in poor conditions, and its a toss up in average conditions.

What kind of long range competition are you shooting?

Benchrest. Last year it was unregistered - informal benchrest matches both light and heavy gun using my 22BR, which loves to blow up bullets. I shot one 600yd match and I believe two or three 1000yard matches. I've got Jim Borden building me a 6.5x47 that will hopefully not blow up bullets, but I think an 8 twist shooting 140s is much safer than a 7 twist shooting 90s!