How do you verify the accuracy of your scale?

[cloverleaf]

So, finally got out a few weeks ago to shoot the 250 Sav. (I made it.... ). Some recent reloads w/ 35 gr of IMR 4064 Showed pressure signs, 3+inch vertical string and hard bolt lift. So Im thinking too hot. When its cold out (30 degrees) these grouped right around an inch or less.
So, What could my issues be?
Checked my scale with a 100 gr BT - I have two and neither registered 100 gr's. Would have hoped they'd be the same. Years ago Dad had the Herters scale checked at the pharmacy. Don't think they'd do that anymore. Its an old Herters scale...not like I can send it back. Sentiment and finances make me want to hang on to it but....

Sorry I'm rambling a bit...and hate typing.

Thanks for your thoughts. CL

 

[truck driver]

As you found out not all bullets weigh what the claim they do.
Your scale is probably accurate but you can get check weights from RCBS and Hornady. Midway or any of the reloading vendors should carry them.
Hope this helps

 

[DrMike]

I have several sets of check weights for calibrating the scale. They are not prohibitive in cost, and they do give a measure of certainty.

 

[Guy Miner]

Yup, I have two 50 grain weights from RCBS.

About as good as I can hope for I suppose.

Guy

 

[jimbires]

I also have check weights that I've used to check my scales with , but they should be handled with gloves or tweezers due to corrosion .
what I do before each reloading session is run a set of bullets over my scale . I've weighed them and wrote the exact weight down , so I know if something is not reading right . I'll weigh each one this way I know the scale is accurate through the range of these bullets . my 55 gr B-tip weighs 55.08 or 55.10 , 85 gr hollow point weighs 85.04 , my 180 AccuBond weighs 180.08 , my scale pan weighs 135.66 ,



if you would want a few bullets weighed , PM me your address and I'll send you a couple .

 

[RaySendero]

I zero
Then check an 85.00 grain bullet I have saved

 

[preacher]

If I allowed my OCD reloading Looney to worry about corrosion on my Check Weights, I'd have to worry about the battery half-life, the wear on the powder pan, the wear on the bottom of the pads, etc. ha

 

[Nimrod84]

Sorry about the late reply and congrats on getting the 250 Savage out. I hope your concerns with your Herter's scale has been resolved, but if it hasn't...

I personally own 6 scales and I typically run three of them while reloading. Usually a Chargemaster 1500, GemPro 250 and a Lyman M5. My goal isn't to have each scale in perfect calibration, scales normally have a precision of + or - 0.1 grains with a resolution of 0.1 grains, so they can be off of the actual weight by a significant margin. I don't use a charge unless at least two out of the three scales are in very close agreement (the M5 and the GemPro 250).

I have had all three drift in the same session due to static electricity, rapid temperature changes and unknown gremlins setting up shop while I am away. Point being, I'm not looking for lab certified measurements, just consistency from day to day and session to session.

RaySendero's and Jimbires comments on using a bullet, case, screw, nut, bolt, reloading pan etc. with an established weight works well to check for drift / repeatability. A couple weights at the low and high ends of your typical charge weights will show if the scale is in calibration and tune. An out of calibration scale can be adjusted to show the correct weight with one check weight, but its linearity might be off (dust on knife edges, bent rod, magnetic damper having issues, etc. a good intro to this can be read at https://www.labdepotinc.com/articles/wh ... scale.html). That is the main reason the Chargemaster 1500 is calibrated at three different weights (0g, 50g and 100g).

 

[ShadeTree]

I do the same as was mentioned above. Zero then check with a bullet. But admittedly not every time, just now and then to make sure nothing has changed.

 

[diverdown]

Over the years there's been quite a bit written about scales/fluorescent lighting. The minimum for scale accuracy should be 6 feet. - just some info.

 

[highoctane]

Check weights are the way to go..I have a 20 gram weight =308.6 grains...50 grams = 771.6 grains. I load nothing that would facilitate my need for anything larger than 50 grams. All thats needed is to weigh those weights and calibrate if needed!!!

 

[jezzolo]

What about time of day?? Will it be off more afternoon or before noon???. What if it’s overcast outside? Omg some many variables. I’m getting a headache and must lay down.

 

[ShadeTree]

My theory is it does not matter if my scale is off 2/10 of a grain by a empirical example of verified weight, as long as it doesn't change and remains off by 2/10 of a grain. I'm not using your powder scale, and you're not using mine.

So as a hypothetical if my notes say I'm loading bullet X with powder B, at 44.5 gr's but it's actually only 44 gr's......as long as that scale continues to precisely be off a 1/2 grain, and I have a way to verify it is remaining consistent, then the rifle and me are no worse off. That's just an example and I wouldn't want my scale to be off by 1/2 gr, nor do I believe it is, but all I can do is check consistency.

I just happen to use a RCBS balance beam scale. Not because I have evidence it's better, I just use what works for me. The zero adjustment that it needs does marginally change sitting at the same spot on the bench, but once it's zeroed it has shown to remain consistent to the tenth in its readings when checked with previously weighed bullets.

 

[preacher]

I gave up on balance beam scales decades ago. I have big hands and it just aggravates me to mess with them. I like simple digital, 9v with two check weights. I calibrate it when I start. If I accidently moved it on the bench, I just calibrate it again. I don't usually load more than 20rds at a time, sometimes less. If I load more than 20rds of one load, I will recalibrate every 20. Its not biggy, and enough to calm my OCD, ha.