Weighing Powder - How precise is good enough?

[jdbove]

I've been more or less forced to look into replacing my RCBS Chargemaster electronic scale for a reason you would never guess. It seems that the 'beep' tone that the scale issues is on the exact same frequency as the warning tone for our dog's underground electric fence, and no matter how far away I try to do my reloading the poor animal is freaking out (along with my wife) until I am finished. At least it gives me a pass to look into upgrading.

This is where it gets tough. As is typical, I've been reading everything I can find online before choosing a replacement, and also as is typical, am reminded once again that when it comes to precision instruments, you get what you pay for.

I had an interesting conversation with the very knowlegeable owner operator of Precision Weighing Balances (www.balances.com) when I called to ask for his advice. It seems he gets a lot of phone calls from 'gun guys' and quickly becomes frustrated with our refusal to acknowledge that if we want to weigh powder charges accurate to .1 grain or less, we are going to have to spend at least $700 on a lab balance.

The gentlemen rapidly dismissed ALL 'strain gauge' based balances as 'junk' and insisted that for this level of precision, only an 'electromagnetic force restoration' balance will suffice. These units START at roughly $700 and rapidly escalate in price to well over $8K. Not the biggest fan of us 'gun guys' he doesn't quite understand how we are willing to drop multi thousands of dollars on 'monster weapons' but won't pony up for the right balance to optimize its function. He pleaded with me to watch his YouTube videos on these subjects (search 'balancesdotcom' on YouTube) and 'spread the word' to the gun guys so he will get fewer inquiries that lead to no sale due to sticker shock.

I think that we can all agree that when it comes to weighing charges, uniformity between samples is probably more important than the true absolute weight of any given charge when creating a batch of loaded rounds. This notwithstanding, there will also be those of us who desire (or require) a very precise measurement of the charge weight as well.

So there it is...how precise does this element of our pursuit of accurate long range shooting have to be? Must we all pitch our RCBS/Hornady/Sinclair etc. 'junk' in favor of a piece of true laboratory equipment?

With my luck, a brand new fancy high dollar lab balance will produce the same **** beep frequency as my current one, only LOUDER. My wife will make me move out.

 

[Topgun 30-06]

Having been a State W&M Inspector for over 30 years before I retired in 2002, I would tell that guy he is FOS!!! I have an OHaus mechanical balance that a friend gave me two years ago when he quit reloading and I can weigh charges within +/- 0.1 grain all day every day using it and my RCBS trickler to finish each measurement. I do 50 from priming to completion in a couple hours and sure, it's a little slower than an electronic combination scale/powder dispenser, but it's relatively fast and nothing will ever go wrong with it compared to anything with electronics involved. I prime all 50, then place the powder in and seat the bullet on each one as I go, so there is basically no way I'm going to screw up. To me reloading should be done in a nice, slow operation so that everything goes smoothly and is fun, not in an "I've got to load 100 rounds in 35 minutes" type mentality.

 

[kcebcj]

My style of reloading is almost identical to Topgun. I use a Ohous 10-10 scale and trickle to finish 50 at a time or less if working up a load.

 

[JOSE A. MARINE]

ISN'T this about precision?

at one time or another I've had two or more scales, at the same time and even digital, and I just cant trust electronics.

yes, I use an ohaus also, and trickle into it. cero problems. of all the scales I've used, the electronics are the slowest(if you want precision).

I usually prep the cases on one day, another day I put the primers, next day I weight the powder and put the bullets, this way has worked all the time with cero mistakes. I shoot competition. but would love to hear from the benchrest friends...

if I wanted to load 100 rounds in 35 minutes I would own a dillon progresive like the one i have for my ipsc shooting. pistol precision is relative for me(i'm a badshot with a handgun..)

from old mexico
Joe

 

[Cover Dog]

I recently did a review on Accurateshooter.com of the MY Weigh GEMPRO 250, a scale that will accurately weigh down to 2/100th's (.02) of a grain. I don't think there is anything remotely close to it for the price of $165.00

http://amzn.to/1JO9Nhk[/url

 

[milanuk]

Ya know... if you read the MANUAL for that Chargemaster, you can turn the 'beep' OFF....

 

[jdbove]

Ya know... if you read the MANUAL for that Chargemaster, you can turn the 'beep' OFF....

Ya know...I DID read the manual, and the method to turn of the beep was NOT listed.

Ya know...if you READ the entire thread you will see that after I Googled the subject I found the way to do so, turned off the beep, and described in the thread how this is accomplished.

Ya know...this thread was ACTUALLY started to spur discussion about the necessity of hyper-precise measurement of charge weight and its resultant effect on long-range accuracy, which it did so wonderfully.

 

[jdbove]

Hey Milanuk...sorry...the vast majority of the replies to this thread are contained in the 'reloading techniques' section of the forum, including the revelations regarding how to turn off the beep...my bad.

 

[milanuk]

Ya know...I DID read the manual, and the method to turn of the beep was NOT listed.

Actually... it is. Page 8, right-hand column, just about half-ways down, under the heading 'Disable/Enable Audible Tone (Beeps)'. The PDF of the manual is here, if you want to check.

Ya know...if you READ the entire thread you will see that after I Googled the subject I found the way to do so, turned off the beep, and described in the thread how this is accomplished.

Hey Milanuk...sorry...the vast majority of the replies to this thread are contained in the 'reloading techniques' section of the forum, including the revelations regarding how to turn off the beep...my bad.

NP... figured I must have missed something whilst skimming thru things. Wouldn't be the first time

Ya know...this thread was ACTUALLY started to spur discussion about the necessity of hyper-precise measurement of charge weight and its resultant effect on long-range accuracy, which it did so wonderfully.

Fair enough... here's my take: in general... the smaller the cartridge, the more noticeable results you'll get from weighing charges out to the kernel - mainly due to the relative size of change you are making. For a .223 Rem where I might stuff 24.5 gn of N150 behind an 80 or 90 gn bullet, one kernel weighing ~0.025-0.03 gn (give or take a bit) probably makes more difference than one kernel of H1000 when dispensing 93 gn for a .338 LM pushing a S300MK. With the former, I can usually see tighter groups, less vertical dispersion, etc. from the uber-precision weighed charges. With the latter... not so much. Then again, a .223 Rem is a little easier to shoot, so it may not be an entirely apples-to-apples comparison.

 

[FAL Shot]

Plus or minus one grain of powder should be sufficient, I would think.

But, some grains of powder are bigger than others.

Then there is the "relative bigness" of cylindrical, ball and flake grains.

When the moon is overhead, the gravitational pull may cause a change in the scale reading, just as it causes a rise in the tides. Tides are for real, so moon pull compensation should get your attention as well. Is your scale moon pull compensated???

Turn off all fans when using a balance scale. Air currents even affect digital scales.

Ditto for vibrations.

And barometric pressure changes.

And scale pointer parallax error.

And earth spin centrifugal forces depending if you live on the equator or nearer the spin axis such as Anchorage, Alaska.

 

[RDM416]

I bought an expensive Sartorious scale about a year ago. It will measure to .02 grains. I dispense my charge with my chargemaster then trickle up or down as needed. More resolution would be useless since a single "granule" of powder will change the reading by .02.

Does it help? Not that I can tell. After using it for a year and comparing my average ES I see no difference. I still use it because I bought the darn thing, but I think .1 is probably good enough even for precision shooting.

 

[dustybrown]

I know this is an old thread but I was loading for my rifles recently and I noticed the odd sized out of normal off color kernel of powder. (retumbo) Is this anomaly going to be an issue with charges out of a charge through ? and I always weigh my charges and trickle to the best my scale will read (5-0-5 RCBS)....
I know a lot of bench rest guys that just weigh every ten or so.....
Its a two part question ?
odd sized and shaped kernels ?
and to weigh every charge or every 5 - 10 ect...
for shooting at 1000 yards and wanting low ES

 

[milanuk]

The point blank BR guys I shoot with (Hunter/VFS BR @ 100/200/300) barely know where their scale is as they throw *everything* (1) and most long-range BR guys weigh *everything* to the nth degree. I've never heard/seen anyone from either group, that only checks weights 'every 5-10'. Maybe its a locale-specific thing...?

In the past I've used N150, which has several different sizes of kernels, with different weights (but often the longer ones weigh almost nothing, while the shorter ones are usually heavier!). If I'm weighing out to a point where that matters i.e. with a really good milligram scale, this becomes noticeable. For a 'normal' reloading scale... don't worry about it and rock on.

(1) While thats 99% true, there is a small group of point-blank BR guys that weigh charges - generally they either pre-load (load all their rounds at home on a proper scale) or else dispense weigh charges at home and then store them in test-tubes or similar vials to dump into the cases at the range.

 

[FAL Shot]

I have the new Hornady balance beam scale, and I can tell the difference when a single kernel of Varget hits the pan. I discovered that it takes about 5 or 6 kernels to equal .1 grain. I paid $65 for the scale at Midway USA. To tell me that I need to spend $700 on a scale that is accurate to .1 grain is RIDICULOUS.

Here is a little secret: tap the tabletop of a beam balance scale as it is settling down. It removes any stiction in the bearing and lets it find true equilibrium. Remove ALL air currents from the area, don't even BREATHE while doing this, and it will be VERY accurate.

You can also remove balance beam scale bearing stiction by playing music really loud and letting it vibrate the tabletop the scale is sitting on. Whatever works for you.

In the clinical lab of the hospital where I was a biomedical engineer, they had a beam balance scale that could literally weigh a fingerprint, and it sat under a glass cover in order to remove all air currents from affecting its operation.

There are plenty of beam balance scales for under $100 that can repeatably weigh to .1 grain or less.

Electronic scales are for quickly weighing brass and bullets that can vary by several tenths of a grain to several grains.

If your powder charge is accurate to plus or minus .1 grain (for a .2 grain span), which means about 10 kernels of most stick powders, you will never notice it in a field hunting situation, but you will in benchrest competition. For long range hunting applications, I would want plus or minus .05 grain, for a span of .1 grain high to low. The $25 Lee Safety Scale should be able to do that.