OT - Powder Scale Accuracy

[Rimfire McNutjob]

I was loading some rifle cartridges recently and I've always been curious as to how accurate my charges are when using my 15 year old RCBS 5-0-5 scale. The book obviously states that the scale is only accurate to within +/- 0.1 grains. Since I'm loading over 60 grains, that seems like a reasonable range but I was wondering if, in fact, the old balance beam scale was really better than was stated.

For large rifle cartridges, I will either throw a short charge from the powder measure or actually use a teaspoon to throw an initial charge into the pan. Then I will trickle until I slowly bring the lines together. After a few charges, you can get pretty good with the old teaspoon.

I decided that I would double weigh my charges and see how I was doing with the 5-0-5. I happen to have a high accuracy electronic scale that is good to +/- 0.02 grains on hand. I got that scale so that I could do some very accurate small charges for a small cartridge experiment ... like 3 to 4 grains of power. So I fired up the electronic scale and let it warm up. I had previously calibrated it. I measured 63 grain charges in my traditional manner on the 5-0-5 scale and then transferred them to the high accuracy scale for a second opinion.

The first five charges of 63.0 grains on the 5-0-5 all measured between 63.00 and 63.04 grains on the electronic scale. It was so close, I just quit doing it after 5 measures and gained a new level of confidence in the old balance beam scale.

I guess what I'm saying is that if you're considering a newer electronic scale for a potential accuracy increase, don't sweat it. It's not necessary ... certainly not after my experience. I was actually really surprised but it looks like that old Ohaus technology still works pretty well. No wonder my extreme velocity spreads are pretty tight.

[J Miller]

I also have an RCBS 5-0-5 scale as well as my ancient oil dampened Redding scale.

I bought the Redding new some 30+ years ago and used it continuously up until I bought the 5-0-5 used on eBay about 4 years ago. The 5-0-5 had to go back to Ohaus due to operator error causing damage to the pivot blocks.

When it came back I purchased a test weight and tried it on both the old Redding and the newly refurbished 5-0-5. Both were were exact dead on with the test weight.

I've never been tempted to buy one of the electric scales for accuracy, but I've heard they are faster for weighing bullets. Not sure that use is worth the cost of those scales.

Joe

[adirondakjack]

AAMOF, the cheap LEE beam scale is as good or better than electronic scales until ya get into some big bucks. Sure, ya have to interpolate, but on a 10 grain charge, one can easily SEE .02 or .03 deflection, an amount equal to a couple flakes of Unique.

[jnyork]

If you are REALLY wanting to know for sure, RCBS and others make a set of scale weights to check your scale.

[Sixgun]

McNutJob, (I really like that name )
yep, the balance scales are "on the money" but.....................you still have to pay attention as they get out of whack from time to time. They have to kept clean of dust, oil etc. as crud gets in the grooves and can set things off. The weight of the dust on the beam alone gives false readings.

I have four scales--two beam and 2 electronic and when weighing a new load, I cross reference AFTER calibrating each scale with check weights, available from RCBS.

I really think most reloaders put too much worry on their charges, especially large capacity rifle cartridges, using medium to slow powders. Take for instance, 1/2 grain either way in a 45 grain charge of 4350 won't matter except in the finest of benchrest rifles.

I throw 99% of my charges and I only disintregrated one gun but thats another story about powder bridging. ----------Sixgun

[Gun Smith]

My 55 year old Ohaus "505" works great. I wonder how many thousands of rounds it's measured. Mine is red with an ivory cover.

[stretch]

I have a 5-0-5, adn a Lyman M-5 beam scale also made by Ohaus.

Both are superb and very accurate according to the check weights.

Repeatability is more important to me than raw accuracy. I imagine
there's some variability in powder lot to lot - perhaps more than
in the scale, especially in large quantities of rifle powder in big
cartridges. (Did that just make sense?)

Still, it's nice to know that 4.5gr of WW231 is actually 4.5gr of WW231!

-Stretch

[TedH]

I've always found my 505 to be extremely accurate. I trust it more than my digital scale.

[Don McDowell]

I've had my Redding balance beam for close to 40 years. A few years back I decided it wasn't accurate anymore and bought one of the new digital scales. That ol Redding was right on the money, charges weighed on it were exactly what the digital said, So I keep on measuring powder with the Redding as I find it faster than the digital, but the digital is really handy for weighing cast bullets.

[Ben_Rumson]

Rimfire McNutjob... Just for grins try re weighing the same charge two or three times on the digital & see if any variations come up..
Iv'e gone with the Lyman electronic system and never looked back.. I get weighed charges in the time it takes to pick up a case and prime it with the Lee hand primer...

[RIHMFIRE]

I have a dillon scale and I just make sure the
fulcrum is clean and has a dab of oil on it, and check it
every ten loads or so....I have more problems with my
powder dispencer....especially with powders like 3031

[220swift]

Well...... I had an RCBS electronic for all of about two hours 15 years ago.... I throw light and trickle and I *really* didn't like that it took 4-5 kernels of powder (imr 4064) to register a change. On the 5-0-5 one kernel is a visible difference.

Dan

[PaulB]

I have the RCBS 10-0-10 (or whatever that is called) and I did have some problems with it at one point. I found it getting sticky and not going smoothly to the desired weight as I dropped powder in. I went to clean it, looking especially at the pivot groove and making sure I didn't have any rust on the pivot wedge. Checked with a magnifier. After cleaning it up it started working properly again.

This scale comes with weights but I never checked before. I need to get in the habit of checking it...

It's good to hear these simple balance beam scales are accurate and repeatable (when they are clean).