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fishbone

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On another post on accuracy of powder measures someone questioned the accuracy of the scale used for checking. They claimed +/- 0.1 gr on beam scales.
Many years ago I used a Lyman beam, and recently bought, and now use, a Readding beam model. I just assigned great accuracy to them without question because of the beam design.
Are they accurate?
For my purpose in load development, repeatability is more important.
Any thoughts on this?
 
Do you have a know, certified weight to practice with?
I believe RCBS has them and industrial scale companies.
Practice with the known weight and see how your scale reacts to build confidence.
Not sure but some beam scales may be adjusted to achieve zero on the scale.
Centerfire
 
They can be very consistent if you use good technique. I like to start with a light load and trickle up to the intended load. This gives me an ES of 10 or less in most cartridges.
 
I like my RCBS Chargemaster combo, but I check it against a beam scale frequently. I also grounded the metal frame to the heavy metal base of my reloading table. Never hurts to be totally anal about these things. The Chargemaster comes with two 50 gram weights and I calibrate it before each use, but I think now I will get a calibration weight kit so I can have smaller weights to cross-check both scales. I see them on Amazon for about 11 bucks. Oh, it got good reviews. I couldn't help myself, I just ordered it! Put it on my wife's card too. Maybe I'll wrap it for her for Christmas! Isn't multi-tasking great?
 
fishbone said:
On another post on accuracy of powder measures someone questioned the accuracy of the scale used for checking. They claimed +/- 0.1 gr on beam scales. Many years ago I used a Lyman beam, and recently bought, and now use, a Redding beam model. I just assigned great accuracy to them without question because of the beam design. Are they accurate? For my purpose in load development, repeatability is more important. Any thoughts on this?
Click to expand...

As long as the instrument you're using can be calibrated, before use, to ensure that the reading you're receiving from it is accurate, it doesn't matter which type scale is being used. The key, is making sure you can calibrate the instrument to a known precise weight and have the ability to adjust it when it is off.

If you can't adjust it, you're always going to have to take the amount it is off, and account for the difference in your measurements. The biggest problem is when the difference starts bouncing all over the landscape. You can eliminate a lot of concerns with an instrument that allows it to be calibrated easily prior to use and provides a self-zeroing function.

For reloading, I like the RCBS Charge Master Combo 1500. It does all the things described above and turns reloading into fun instead of a chore. It's a little more expensive, but if you look at the current price plus rebate and the price one pays for a good beam scale, the difference in price might be very manageable. This site has always been a great source for a deep discount on the RCBS 1500: http://www.natchezss.com/product.cfm?contentID=productDetail&prodID=RC98923&src=exrbSrch To get the $75 rebate I added an item over $10.10 to qualify.

Here's a good video on the 1500 by Sinclair that covers many of it's features: http://www.youtube.com/watch?v=PckYE6K6sYY

The best price is found by shopping around. However, Natchezss is hard to beat.
 
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One way to tell how your balance scale is performing is to repeatedly weight the same object. It the pointer does not come back to exactly the same place every time, you have issues to resolve. Scales, even new ones, benefit from tuning. Another little demonstration that can be instructive is to change the beam setting by .1 grain after you have balanced the scale, with something in the pan. One of the issues is that the beam moves so little with a .1 gr. difference. Parallax is another problem. There are workarounds, such as this. (not my video, but I have a similar setup) http://www.youtube.com/watch?v=ZCs0Y7HH2zA
http://www.youtube.com/watch?v=HMX4lq90Fy4
http://bulletin.accurateshooter.com/2012/02/tech-tip-use-mirror-and-magnifier-with-beam-scales/
http://www.youtube.com/watch?v=U57jnitmLP8
 
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I’m not that worried about the accuracy of my power scale, just that the will repeat each time I use them. Say you are working on a load that is between 34 and 36 grains. I start with 34 gr. on my beam balance scales (RCBS). Load as many rounds as I want to test, if this is a good load I stay with 34 gr. on my power scales. I don’t go to another scale and load with it. I don’t care if the scales you start with reads in “rocks” if you find a load that shoots good and it is 34 “rocks” use it. I think the repeatability of you scales is more important than the accuracy. I start on the low end and work up. Just my opinion.

john
Mims, Fl.
 
I feel my confidence in the inexpensive beam scale was right. Here's my take from the above posts.....
The knife edges must be sharp and clean.
A stable base
A needle added to the pointer for better resolution (A step farther would be magnification).
Elevate to reduce parallax.
Test with measuring the same wight to confirm repeatability.
Now, with the above being done, loads should be very uniform. Maybe not the exact weight recorded, but tuned to what was read out, and will be weighed to the same setting for the next loading.
To my thinking that should be a dead nuts weighing system. I am not loading to a stated weight, but to what shoots best and recording what the scale reads requiring me to always use that scale and set-up.
 
this can be very inconsistant with a reloading beam type scale...
you must touch the beam and getting it moving AFTER every add to the pan...the magnetic dampening resist movement....
very easy to be off a tenth or more if you simply trickle and let the beam come up by itself.

the gem pro 250 seems to be good...we need more feedback from users.

mike in co


Terry Balding said:
They can be very consistent if you use good technique. I like to start with a light load and trickle up to the intended load. This gives me an ES of 10 or less in most cartridges.
Click to expand...
 
this is not much of a check...both intruments are plus or minus 0.1...so sorta hard to check against each other.....the tool used to check the first tool must be MORE accurate THAN THE TOOL BEING CHECKED.
mike in co

vtmarmot said:
I like my RCBS Chargemaster combo, but I check it against a beam scale frequently. I also grounded the metal frame to the heavy metal base of my reloading table. Never hurts to be totally anal about these things. The Chargemaster comes with two 50 gram weights and I calibrate it before each use, but I think now I will get a calibration weight kit so I can have smaller weights to cross-check both scales. I see them on Amazon for about 11 bucks. Oh, it got good reviews. I couldn't help myself, I just ordered it! Put it on my wife's card too. Maybe I'll wrap it for her for Christmas! Isn't multi-tasking great?
Click to expand...
 
To be clear, I shoot long range benchrest. If I shot point blank, I suppose my methods would be different.

I did an experiment this afternoon using my RCBS Chargmaster, GemPro 250 and RCBS 10-10 scale. All 3 were set up and zeroed and were calibrated with their respective weights and procedures. The test was performed with N540 powder as it has the smallest/lightest kernels (about 5-6 kernels) per .1 grain of any of the powders I have on hand.

Test 1: 30 grains N540, repeated 3 times.
1.) Throw charge with Chargemaster.
2.) Weigh and trickle up to 30.00 grs. on GemPro.
3.) Dump charge in pan of 10-10 set at 30.00 grs. Beam centered exactly on zero.

Test 2: 30 grains N540, repeated 3 times.
1.) Throw charge with Chargemaster.
2.) Weigh and trickle up to 30.00 grs. on 10-10.
3.) Dump charge in pan of GemPro. Scale read exactly 30.00 grs.

The 2 above tests were repeated with charge weights of 43.00 grs. and 65.00 grs. Results were the same as with the first two tests.

The scales were checked after the tests with their respective calibration weights and none had changed.

Conclusions:
The 10-10 is a great scale. So is the GemPro. The Chargemaster is perfect for throwing charges quickly, but not as accurate (+/- .1 grs. or more) as the other two scales.

I have been using the GemPro to verify and trickle to the proper weight as it is takes less time to do than with the 10-10. If I were in a situation with no electric power, I'd be perfectly served weighing charges with my 10-10 only.

Jerry
 
jerry,
nice report...
the issue with the 10-10 is not so much its ability to weigh, but the user.
people that trickle seldom move the beam after adding powder....instant error.
try the test with a large kernel.
do the test in reverse...10-10 with a large kernel..then on the gempro....
mike in co
drumcorpschamp said:
To be clear, I shoot long range benchrest. If I shot point blank, I suppose my methods would be different.

I did an experiment this afternoon using my RCBS Chargmaster, GemPro 250 and RCBS 10-10 scale. All 3 were set up and zeroed and were calibrated with their respective weights and procedures. The test was performed with N540 powder as it has the smallest/lightest kernels (about 5-6 kernels) per .1 grain of any of the powders I have on hand.

Test 1: 30 grains N540, repeated 3 times.
1.) Throw charge with Chargemaster.
2.) Weigh and trickle up to 30.00 grs. on GemPro.
3.) Dump charge in pan of 10-10 set at 30.00 grs. Beam centered exactly on zero.

Test 2: 30 grains N540, repeated 3 times.
1.) Throw charge with Chargemaster.
2.) Weigh and trickle up to 30.00 grs. on 10-10.
3.) Dump charge in pan of GemPro. Scale read exactly 30.00 grs.

The 2 above tests were repeated with charge weights of 43.00 grs. and 65.00 grs. Results were the same as with the first two tests.

The scales were checked after the tests with their respective calibration weights and none had changed.

Conclusions:
The 10-10 is a great scale. So is the GemPro. The Chargemaster is perfect for throwing charges quickly, but not as accurate (+/- .1 grs. or more) as the other two scales.

I have been using the GemPro to verify and trickle to the proper weight as it is takes less time to do than with the 10-10. If I were in a situation with no electric power, I'd be perfectly served weighing charges with my 10-10 only.

Jerry
Click to expand...
 
mike in co said:
jerry,
nice report...
the issue with the 10-10 is not so much its ability to weigh, but the user.
people that trickle seldom move the beam after adding powder....instant error.
try the test with a large kernel.
do the test in reverse...10-10 with a large kernel..then on the gempro....
mike in co
Click to expand...

Thanks Mike,

I always give that little nudge to a beam scale. Agree....only way to do it.

Have also found with the GemPro that when I just trickle up to weight and do not give the pan a lift and set it back on the stage, I usually wind up overweight. Best and quickest results come for me by lifting the pan when I'm within a kernel or so, let the pan down and read the number and repeat until weight is reached. Actually took me much longer to type these couple sentences than to weigh the actual charge.

I think doing the test with large kernel powder would only show how difficult it is at times to get the beam scale or the digital to settle right at zero because some of those kernels can weigh .03-.04 grains. I'm satisfied and convinced with the results I attained.

Jerry
 
I have a bench scale for sale. I hope it would be the best for your need. here I have some information about the " Bench Scale " . Its 500lb/0.1lb legal for trade. Bench scale It features a stainless steel 18"x18" platform. In an affordable prices.
Ntep Scales
 
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Basic repeatably check

I used to think the electronic scale I was using may not be any more accurate than +-.1 but figured that didnt matter as long as it was repeatable.
I was wrong. I started weighing bullets one day and then went back and started to check then ones I had weighed..... oooooppppsssss.
I found that if I took one bullet and weighed it waited a while and reweighed it and kept doing this with several different bullets then they could weigh +-.1 for the same bullet. And yes the room was perfectly set for temp breeze and the like.
This was an RCBS scale from a couple of years ago and a new one also.
FWIW
 
I have, or have had 5 balance beam powder scales and 7 electric ones. I didn't find one that was a marked improvement until I got a MMX-123 or whatever they are, then AND ONLY THEN, could I actually visually and easily and repeatably see one single kernel of powder.

Put it on,

take it off,

put it one,

take it off,

go have lunch, come back, put it on....

and SEE it.

From this single thing I easily found single digit ES and instantly relegated $1000.00 worth of tools to the junk heap.

for those of you who don't want nor need single digits, please refrain from muddying the waters with irrelevant commentary about "winning with charges dipped with a spoon."
al
 
For those of you on a tight budget, I have spent considerable time with the same model scale that Al has, and a Gem Pro 250 that costs less than half as much, and while the exterior quality of the Gem Pro is not in the same league as the more expensive scale, its weighing performance seemed to me to be. Also, I have read a comparison test that agreed with my conclusion. They both are strain gauge type scales and as such can suffer from the same sorts of issues. The next step up is a scale that works on the principal of magnetic force restoration, and those are twice as much as Al's scale. You may find this to be of interest. http://bulletin.accurateshooter.com...-comparison-gempro-500-ay123-sartorius-gd503/
Although the scales compared are not exactly the same as those that we have discussed they are very close.
 
Chronographs.

Back when Henry Childs first spent time here he and others did a bunch of chronograph testing. And a bunch of engineering types discussed and weighed the "why" and the "how" of chronograph accuracy. I've still got photos and data-sheets stored in my computer, stuff it'd take me days to decode but stuff I understand just well enough to trust the veracity of the guys sending it.

I also did some "testing" my way.

And I've a fairly good handle on "luck" and the laws of averages.

Bottom line, if you've a chronograph of any sort and you consistently produce loads that are "really close together" velocitywise...... and if other loads are consistently "NOT really close together," velocitywise.........


Then worrying about the "accuracy of your chronograph" is kinda' like mistrusting your compass.


Just how lucky would you have to be to string together a bunch of 6-digit ES spreads? Shucks, if you can, and it's luck, then you better go buy a lotto ticket. Better yet, bring your Model 94 30-30 to a group match and let the wind "blow 'em in!"


opinionby
al
 
F...

FBecigneul said:
for those of you who don't want nor need single digits, please refrain from muddying the waters with irrelevant commentary about "winning with charges dipped with a spoon."

Yes but we need a thorough test done and reported here on Chronograph accuracy.
Click to expand...

I use the two lb coffee can method...

Clean and dry a wide mouth Folgers plastic can

Fill arf with H4198

Prep cases

Pick up a case and scoop through powder till full

Bang on table to settle

Empty till powder is halfway up neck

No stinkin scales !!
 
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