digital vs beam scale

[Bill C]

Hi all, there was a recent thread about digital scales vs beam scales. I recently purchased a Lyman Gen 6 and have been testing and evaluating for about two months and about 1000 reloads. FWIW, just a data point for anyone who is curious, here are my results

I considered a digital scale for three reasons:
1. Efficiency. Beam scales are slow.
2. I was skeptical that my RCBS 5-0-2 was not holding zero. After zeroing the scale, I would periodically check to make sure it was still holding zero. It was not.
3. Reloading bench/setup is built around reading a beam scale at eye level. Either elevate the scale or lower your position relative to the scale.

Today I tested identical loads except one batch was loaded with the beam scale the other with the digital
1. Rifle was a savage model 10 chambered in 223 with a 1x9 twist
2. Accuracy was identical as was POI. Both grouped 10 shots into 1 MOA
3. Velocity differed on average by only 12 FPS.
4. Standard deviation was 11 FPS (beam) vs 21 (digital)*
*A similar load using only a different bullet (52 BTHP) produced a std. dev. of 10 FPS

I'm hesitant to make any conclusions because I'm not convinced of anything. I would need to conduct more tests however I have neither the time nor the inclination for such things. I was very surprised at the performance of my beam scale loads because my bias going into this was that it wasn't holding zero. I didn't expect such a tight standard deviation. Perhaps the beam scale, even if it doesn't hold zero, is still more accurate than a digital scale? Who knows.

At any rate, I'm going to continue to use the digital scale as it is a good balance for me between time, accuracy, and speed.

Bill

[foxx]

Thanks, Bill.

Question: What do you mean your beam scale does not hold zero? How can it not? You are measuring/comparing mass... there's no springs, etc. Mine is RCBS and you reset to zero by turning one leg up or down until it balances at zero with nothing in the pan. Now, I have noticed that, when working, my bench will vibrate and cause the balance to moved just a bit on the bench... because the bench is not perfectly smooth and level, as it "scoots" across the bench, the legs sit at different spots and different heights. My solution was to draw an outline of the scale's feet with a black marker on my bench, along with a witness mark for the leg that spins to adjust up and down. That way, if it moves (which it does) I can see it. Regardless, I recheck for zero frequently.

[Bill C]

I will set the scale to zero prior to using it. After every 20 or so charges that I would weigh, I would set the scale back to 0.0 grains and the beam would read "zero." It would be 1/10-2/10 high or low. I hope that makes sense.

Bill

[foxx]

No, I get it. I meant that rhetorically. Unless there is a major mechanical problem with the scale, or there is some grit/grime in the pivot points of the fulcrum, it can't be wrong. Therefore, my guess is your scale is shifting on the bench as was mine. It's not the scale, its the set-up.

[foxx]

Well, to clarify/correct myself...

The scale can be wrong, (read different masses incorrectly) but it should always return to zero when the different weights are returned to zero. Unless it's been moved, zero will always be zero on a beam scale. (Everything else might not read correctly as you go along the beams, but ZERO is ZERO and you are comparing the same mass both times, now or 30 mins later or 1 month later).

Sometimes there are magnetic fields around the bench that will interfere. Some lights can cause this. But I bet you dollars to donuts your scale is moving around on the bench.

[Bill C]

Well, to clarify/correct myself...
But I bet you dollars to donuts your scale is moving around on the bench.

Scale isn't mounted to the bench...it doesn't move.

Bill

[foxx]

So you are sure it's not moving or the "zeroing leg" isn't spinning on while you play with it? My guess is you have some magnetic fields pulling on it, then. Regardless, you're doing good, you demonstrated that.

[Bill C]

Trust me Foxx, I know how a beam scale works and I understand the point you're trying to drive home. It is inconceivable to think that a beam scale can malfunction because unless the magnetic pull of the earth has changed or there is some outside interference "it can't be wrong." Right.

Bill

[foxx]

Sorry if I sounded condescending. Didn't mean to. Just chatter.

[foxx]

I can't help it! LOL (Laughing at myself)

I have also found that single grains of powder can get stuck to the bottom of the pan on my scale. It's there before I zero it and it falls off or it jumps on there after zeroing the scale. Sometimes they get caught in the hanger that cradles the pan. That's "messed up my zero" before, too.

[Robinhood]

Inspect the pivots of the beam. In good lighting you may be able to see flat or damaged spots at the sharp edge of the fulcrum.

[CharlieNC]

I bought a tuned beam from Scott Parker, and it returns to zero every time. He will not tune many new makes of beams because of the excessive slop in the pivot mechanism which leads to this problem, and also translates to lack of precision when weighing. The cheap digitals drift, and do not respond accurately when trickling. From your sd it sounds like your beam is better.

[GaCop]

The only thing I found my digital good for is weighing brass. CherlieNC is right, the digital doesn't respond well to trickling at all, hence my use for only weighing brass.

[cowtownup]

My beam scales do the same thing.. They don't return to zero every single time. I have digital scales and they read one grain higher than my beams. I'm so confused with scales right now its not even funny. I immediately clicked on this thread when I saw the title... LOL

[foxx]

Cow, I know what you mean. I put more confidence in my beam scales, though. As I described above, it usually doesn't return to zero because it moved or there was a grain of powder hiding somewhere either when I originally zero'ed it or when I recheck. On the other hand, I have also noticed that if that little pointer is just a millimeter or two off of true zero, it's close enough. It's amazing (to me, anyhow) just how sensitive that scale is. If it won't return to zero and you are certain the leg that adjusts up and down so as to "zero it" didn't turn on you, or it didn't shift around on its platform or something like that, then it's probably some atmospheric change that's interfering. Magnetic fields from lights or a slight breeze will affect it. SO will anything that is in the little fulcrum point of the balance. To me, if you have a scale that won't return to zero and nothing has moved or changed, then it is defective and the company should replace it. It's one thing to say it isn't calibrated as precisely as a million dollar apparatus, it's another to say it won't go back to zero every time you test it. I really don't think you/we/they are expecting too much for it to do that. But you gotta be sure there isn't something else affecting it.

Good luck everyone. Really not trying to sound like an arrogant expert that's telling you anything you don't already know from junior high physical science class, just trying to encourage us to think it through and look for possible solutions that aren't necessarily the fault of the scale.

[tufrthnails]

I know my digital is jacked up I can't get the same reading on the same exact charge repeatedly. Usually just a .1 or .2 off occasionally .3 but dang that is irritating. I only use my beam scale. Maybe one day I will get one that cost more then $70 but hey id rather buy powder!!!!!

[cowtownup]

Its hard to buy that $100 scale when there is $25 dollar Varget sitting next to it on the shelf... LOL

[Bowguy]

CharlieNC +1 - Scott Parker Re-Manufacturers excellent beam scales.

[mattri]

FWIW I've been having great success with a GEM PRO 250- will accurately and repeatedly register one kernel of powder, returns to 0 and consistent SDs in the single digits. I leave it on all the time and re-check it with a set of check weights periodically.

[ger42]

Sent my RCBS scale to Scott he is shipping it back tomorrow. I'll post my observations when I get it.
Now I have to find a place to mount it where nothing will interfere with it.