Powder scale accruacy

I would have your scale tuned and it will be better, i noticed the difference from a factory scale. You could look up a thread on tuning it yourself, i think Boyd did it. An Omega powder trickler is a plus also. If you can keep it under a .1 you will be fine for now. Annealing and neck tension are critical so i would give that a lot of attention. Bullets are a huge deal also,trim and point and bearing surface +-.001. There are more but i don't want to get into that till you understand and address these point first……… jim
 
I kind of missed the part about the scale, You are on the right track. I would invest in the Omega trickler,they work great and very fast……. jim
 
Hi Jim,

Thanks again for the help. I appreciate it very much.

My scale is tuned. I think it's the same guy that makes the Prometheus unit did it. I bought it second hand, so I'm not 100% sure.

I have a Ken Light annealer. I'm not very good in using it. Any tips that you might have about setting temperature would be greatly appreciated. I've used the vice grip method that Ken recommended. I'm just not confident about it. It's also a pain in the patootie to adjust the torches each time.

I read that you polish the inside of your necks. How do you do it?

I've been using the Imperial unit to lube the inside of the necks as part of my longer-range rounds. Is that what you do?

I have not been trimming or pointing? Can you recommend specific tools?

I have been sorting on base-to-ogive. I use a Redding neck sizing bushing of the bore size and a dial indicator in a small fixture. It seems to work. I first started to use the Sinclair hex nut comparator rather than the Redding bushing, but it was too tall for the fixture.

The last batch that I did were Berger 6mm 90 grain BT. On the base-to-ogive, the distribution was bi-modal. I found that very interesting. The lower had a lot more bullets in it, but there was enough in the upper that I used them for my initial sight in and recording come-ups.

Best regards,

Greg Jennings
 
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I used the vice grip deal, Templac…… ended up on a visual method. Darken the room,and set the dwell time to you just see a fait glow start. I only use one torch and i set the pencil point 1" long,that way my heat is close to the same every time. trimming and pointing i use Hoover's set up….. Sorting, Bearing surface not base to ogive, see if Mark King still has the Bearing surface comparator,this is the best method. I use a force indicator to seat the bullets and keep the in sets. I never use lube in the neck to seat the bullets. PM me if you need more info……… jim
 
I recently started a method that I like using the 10-10 scale. I touch the empty pan to get it to oscilate and trickle up my charge. I then see the needle go above and below center until it reaches my charge weight. I then touch again to stop it and check where the needle settles. This to me makes sense as the accuracy will vary depending on how the knife settles in the scale. The beam can become off centered putting it too close to on side or the other.
 
With a 505 or 1010 scale that's been kept in shape or tuned up, you'd have to be pretty sloppy to not beat 0.1 grain accuracy.
 
stool said:
that is a fair method,IF plus or minus 0.1 is good enough for you.
for some of us it is not.
Click to expand...

To clarify, I drop a charge a little light with a Belding and Mull powder measure then trickle up with the oscillation as previously mentioned. I am dead nuts when finished. I find the pan moving until then makes the beam more responsive.
 
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I thought I would jump in here and throw in my two cents. After talking to a gentleman who tunes beam scales, we both agreed that you should throw a few tenths under and trickle up until the needle lines up, but doesn't go past. This way the charge is done in one pass and you're not waiting until the needle settles, it's all in one trickle up to zero, if I go past I dump and do over, make sense.
Dave T
 
From your post, I wonder if you have spent much time with a tuned balance. Recently I bought an older RCBS 505 and tuned it. Then I set it up with a web cam on the end of the beam and balance reference mark, so that the camera was about a half inch from the scale. After carefully zeroing the scale, I dropped a single piece of Varget in the pan, and saw a small deflection, and continued with additional pieces of Varget, each moving the scale progressively farther from zero, then I set the scale to 0.1 grains, with the four granules in the pan, and it came back to zero. Somehow I doubt that your remarks about balance scales and what they are capable of, are based on any sort of experience with a really well tuned one, and what can be seen with the use of a web cam, so that there is no possibility of parallax, and the image is greatly magnified.
 
Boyd, I use a tuned beam scale, would you agree with my method of trickling up until the needle lines up and not going past?
Dave T
 
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My wife and I visited a museum once that had a handmade double pan balance made in Germany. It was in a glass case so as to protect it from any breeze from disturbing it. It was a work of art and i would suspect it capable of extremely good accuracy.

Very interesting discussion but as my father once said "Everyone to their own taste" said Mrs O'Leary when she kissed the cow.
 
ekp said:
My wife and I visited a museum once that had a handmade double pan balance made in Germany. It was in a glass case so as to protect it from any breeze from disturbing it. It was a work of art and i would suspect it capable of extremely good accuracy.

Very interesting discussion but as my father once said "Everyone to their own taste" said Mrs O'Leary when she kissed the cow.
Click to expand...


Now waitaminnit....... I thought Mrs O'Leary burnt Chicago down with a cow....??? (apocryphally)

I think your Dad was mixing metaphors :) I like that...

My Dad used "ever'body to their own notion said the old lady when she kissed the cow"
 
I can safely say that a tuning of the balance beam is better, the way you use it will make it more consistent. The point is 4 kernels of Varget is a tenth? I only use Varget to fire form and i do weigh the loads on the GD 503 and i do hold them fairly close. I do know with RL-15 the size difference of one kernel can be weighed on the GD503……. jim
 
stool said:
the part you missed is
THE SCALE IS DESIGNED FOR PLUS OR MINUS 0.1..
no matter how good your technique...
on a bad day even worse than plus or minus 0.1....

without a BETTER scale to check your work, you do not KNOW the actual accuracy of your work.

it is simple math......

it is why others use scales that are plus or minus 0.02 or less....
Click to expand...

You are confusing resolution and precision. The resolution on the 505 beam is 0.1 grain. One in decent shape is considerably more precise than that.

As you say, you do have to have a scale with better resolution and at least as good precision to verify it. I do. There are benefits to working next door to a research laboratory.

For an easy, practical test, clean up a 505, set it up carefully, set it for X grains of powder, drop X minus a skosh, trickle up to it watching the zero line carefully. I'd suggest using a magnifying glass and something to eliminate paralax. I use a web cam. You also need to use a wind box.

After it settles in as close to X as you can get, drop one kernel at a time till you see movement. Let that movement settle out. If your 505 is like mine, it will settle to a minutely different spot. You now have a pretty good approximation for the practical precision in units of kernels for your powder. After all, we're weighing kernels of powder, not nanograms of unobtanium.
 
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I think that for most purposes actual load adjustments, for tuning, of .1 gr. are small enough, given the nature and number of other variables that come into play. What I am looking for, which in no way disagrees with your post, is something that I can see when repeatedly weighing the same thing. I would like the pointer to come to rest in the same place, time after time, and as you mentioned, a web cam gives a much better view of what is going on. These inexpensive scales can be made to work much better than they did when brand new. One little tip, I believe that the primary cause of blunted areas on the knife edges is lack of attention when the beam is placed on the scale. It is easy to get in a rush and come down on one of the agate retainers. Now, I take the extra second to put the far end in, forward of it's final position, and slide it all the way to the back before rotating the beam so that the front knife edge comes into position in its agate support, missing the front retainer. Then, after finishing the assembly, I center the beam so that the ends of the knife edges do not rub.
 
Stool, I learned that i move one thing at a time to see if there is an improvement. When it came to powder, i started with a a RCBS digital scale i shot in 7" i used a 505 a little better not much. Went to a tuned scale much better, groups were smaller and with the GD503 and annealing, bullet trimming and pointing and a Juenke machine and seat depth measurement more precise and a seating force indicator the groups dropped to the 2's @ 1000 it is a sum of all parts. Now we come to barrel quality…………. jim
 
I was not talking about variation of charge weight within loads that are shot on the same target, but rather the target weight to which they were loaded. Given that long range is preloaded, and conditions can vary from what was predicted, I would guess that two perfect set of loads that were intentionally loaded .1 apart, in the center of a node, would be hard to distinguish if each were shot on a separate target. I fully understand the concept of keeping the variance of charges to the absolute minimum to avoid one source of vertical dispersion in groups shot at long ranges.
 
Isn't the circumstance that, by precisely weighing powder, a 1000 yard shooter can position his load at a predetermined point in a node such that it will suffice for changes that he might predict for the day. To the contrary, a 100/200 yard benchrester's metered charge is already absorbing a higher degree of a bullet's sweet velocity range such that he can flip out of that zone as conditions change.

Disclaimer: Not a short range benchrester.
 
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