GemPro 250 or RCBS 10-10 scale?

B

bjld

Guest
Hi all

Electronic scale or beam balance for the same money?

I changed from using a powder thrower to an RCBS Chargemaster to avoid cut kernels of powder, but I've never felt perfectly happy relying on the Chargemaster's precision.

I saw an online review of the GemPro 250 with reference to the manufacturer's claimed resolution of 0.02 grain and wondered how it would compare against an RCBS 10-10 beam balance, since they have similar prices.

The 10-10 has a clear high contrast "window" of the large zero range of the scale. I like this analogue scale because your eyes can watch the beam drift around the zero and slowly come to a stop.

Both a beam balance and an electronic balance are sensitive to wind drift, but the beam balance provides enough visual disturbance so you know when it's settled again.

I use electronic balances at work and I'm happy with them because my employer knows you get what you pay for. But I always balance centrifuge rotors with a beam balance and it's smooth and easy to do.

I used an ultracentrifuge years ago that spun a rotor about a foot across to 55000 rpm. The chamber had to be pumped down to a vacuum before it could do it. It made sense when I was told that I'd have to balance the loads on opposite rotor heads or the heads would self destruct. My instructor smiled and said "use the beam balance, it's easy" and as I added weight to one side or the other the point of the beam would settle gently on the zero. The rotor were machined out of solid aluminium or titanium and had to be washed afterwards in a special detergent and deionised water so no surface corrosion could weaken them. I used the "cheap" aluminium rotor that only cost $40k. The titanium rotor was for really fast runs.

You can't see a strain gauge at work inside an electronic balance and I don't like waiting for a digital scale to zero. And then there's the warm up time and the need to filter your power supply. It is a good excuse to not have a phone to answer, though.

The beam balance is easy to level and immune to electrical malfunction. Maybe I'm just old...

Ben
 
Do yourself a favor, go to Ebay, look up Labratory Balances and buy one of them that will read grains. I am told that Mettler is a very good one. Most of them are in a plastic cage which has a door. Buy the best and cry once.
 
I have a gempro 250 works great to weigh cases, bullets,etc. but it drifts to much to weigh powder charges on it. I like the balance beam better to weigh my charges just for the reason you indicated and once you weigh them out and check them on the gempro they both read the same. I have an old ohaus same as a 10-10. The gempro does read in grains.
 
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The name Ohaus has jogged my memory - I've used their beam balances in the laboratory in the past. And you've reminded me that the RCBS 10-10 is an Ohaus by a different name. I remember thinking that it was probably a quality beam balance when I bought a 10-10 years ago. I've come full circle now: first a powder thrower, trickler and a beam balance, then an upgrade to a 10-10, then moving to rely entirely on a Chargemaster. Now I think I'll have to buy another 10-10 to trickle charges up to weight after throwing them low and uncut from the Chargemaster first.
 
bjld said:
The name Ohaus has jogged my memory - I've used their beam balances in the laboratory in the past. And you've reminded me that the RCBS 10-10 is an Ohaus by a different name. I remember thinking that it was probably a quality beam balance when I bought a 10-10 years ago. I've come full circle now: first a powder thrower, trickler and a beam balance, then an upgrade to a 10-10, then moving to rely entirely on a Chargemaster. Now I think I'll have to buy another 10-10 to trickle charges up to weight after throwing them low and uncut from the Chargemaster first.
Click to expand...

I use my ChargMaster just as you plan to. I use it to throw charges about 0.3g low and trickle them up to weight using my Ohaus 10-10 (Yes, it's an older than dirt Ohaus with their name on it). Based on my experience, you are right not to trust the ChargeMaster with out a check weighing on a beam balance.

I go one step further and set the beam balance to indicate zero using check weights as close to the planned charge weight as I can get, then I adjust the vernier on the scale to the required charge weight. That gives me better repeatability from session to session and pretty much eliminates errors from the scale being moved so it's tilted differently.

Fitch
 
Ben,
You should do a search. There have been several posts on this subject over the last few months. Each time they usually get pretty heated and even more than a little nasty because of the attitude/personality of some posters.
 
Digital v Beam Balance

As an optical engineer who has used a variety of analogue and digital measuring devices over the years my view on DvA goes like this. Every measuring device needs to be calibrated to read true in what ever environment you are using it in.

Most digital reloading scales do not allow the user to recalibrate. A beam balance usually does by allowing the foot screw or levelling device to zero out before use. So unless you are prepared to spend quite a bit of money on digital and unless the accuracy is a necessity stick with the beam as I have proven under a variety of conditions that they are as accurate the the cheap digital.

Andy.
 
The more I remember about my original Ohaus/RCBS 10-10 balance beam the more I like it. I remember using the poise weight to level the beam and then zeroing it, done so easily with the adjustable feet and observed so easily because the entire mechanism was just a beam on a knife edge pivot.

I don't like trying to look directly down onto a bubble level to avoid parallax and fiddling with the feet on a digital balance. And levelling should probably be done 24 hours before calibrating and rezeroing the GemPro250. Which could probably do with another few hours to settle down again. Geez, then I'd find myself checking the calibration again before finally being happy.

At least at work someone from Engineering sets up and calibrates the electronic balances. I like being able to look at the maintenance sheet on the front of the balance and be reassured that it'll work okay. It's different at home when you're trying to squeeze the most consistency out of your own work.
 
ok....what is your desired accuracy?
what type of competition or just hunting plinking loads ???

a beam scale (10-10) is plus or minus 0.1 on a good day, the electronic scales of lab quality are down in the .02/.01 range....much eaisier to load with precision.
decide on your needs then spend the bucks.
again do the search..this has been discussed many times...its about your need and your money pretty simple.

mike in co
 
I should listen to Vern's advice but...

I think the sensitivity of the 10-10 is much better than +/- 0.1 grain because the beam has so much travel around the zero mark - what I called the "window" in my original post.

As for the precision? I remember the beam settling nicely on zero every time I replaced an empty pan.

But it sures beats the hell out of waiting 24 hours before getting a stable calibration from an electronic scale.

I've got a $20k scale in my lab that weighs down to the ug range (0.001 mg) - the government here in South Australia has given me a controlled substance license and they like me to keep a really good track of the drugs.

It has electrically operated doors on either side and even then it sits inside a box to keep air movement to a minimum.

I hate the damn thing but it's the only thing that'll do the job.

But, I've achieved a lot of precision with beam balances in my time and once upon a time I used to weigh very small amounts of drugs with them and the government was perfectly happy.

I only shoot palma and F-class so I'm fussy with my loads, but the discussion on this board has helped my memory and I think I'll go back to the 10-10.

I just like knowing how it works and seeing it in action.

That's me done - please don't flame me for not searching the forum first.

Regards
Ben
 
i think for palma and f class the 10-10 is a good choice....................

but dont knock modern quality electronics...no 24 hour warm up..more like one or less for the mx123 and its big brother.

mike in co
 
Just more on the GemPro 250...

http://bulletin.accurateshooter.com/2011/08/review-of-the-gempro-250-scale-from-my-weigh/

Right at 3 years I have had mine.... Most of the time I leave it on (AC), on it's anti vib pad on a solid bench... I check the scale with it's check weight every few days.... 308.65gr... I typically see a +-.15 range without calibration... Once I calibrate it, it's ON. A "drift" of < .08 is typical over hours of use with just a touch of the Tare button on an empty calibrated tray every now and again ... Just my findings. Solid little scale.

cale
 
In discussions with two new GP 250 owners recently, they're not nearly as happy with theirs as I am with mine. Mines a 150 actually, older. But the same scale. The amounts of drift people talk about are quite a bit more than I experience. But I do treat mine well. For the money, I'd say it's very hard to beat. And, accuracy aside, it's a whole lot faster than a beam. To me, speed is the number one selling point for the scale. I can work with the repeatability, the speed I'm handcuffed on so they better have that built in, and they do.

Keep the old beam scale for those days you're just not sure. Both need to be verified once in a while.
 
Drift always seems to come up. Is drift being referred to the scale drifting during use or if its sitting idle for several days? Maybe one is referring to drift when their a/c kicks on and starts a light breeze that the scale can detect. Seems like "drift" is a loose term and can mean several different things. Now,is it really much of a concern? Just calibrate when "drift" is experienced and start loading...
 
For weighing cores

The GP250's are great little scales. We use two of them side by side with a check weight resting in between. We leave them on 24/7 and this has been for the last fours or five years. We do pick up drift, but both don't drift at the same time so when there is a difference we use the check weight. They do like the temperature to be somewhat consistent, most of the drift will be in the early morning, then they settle in for the rest of the day. I don't know if that is temperature related or lack of use related, but when they start getting exercised, they settle in. We have had to send two of them back, the last one was five years old, used so much the plating was worn off the pan tray, it looked a little rough, but in two weeks they sent us a brand new one.
The prices on the site caroby posted are very good and I think I've sold myself into ordering another one.
Charlie and Cheryl Hood
 
bjld said:
...............

I think the sensitivity of the 10-10 is much better than +/- 0.1 grain because the beam has so much travel around the zero mark - what I called the "window" in my original post.

As for the precision? I remember the beam settling nicely on zero every time I replaced an empty pan.

Regards
Ben
Click to expand...

Ben, trickle a few kernels on, see how many kernels you need to register a change. (Some of us (well, one of us :) ) believe that a kernel is worth 3-5fps)

al
 
al.
a kernel of varget or of 8208.....(how about 4227...)

context, context context....
mike in co
alinwa said:
Ben, trickle a few kernels on, see how many kernels you need to register a change. (Some of us (well, one of us :) ) believe that a kernel is worth 3-5fps)

al
Click to expand...
 
I just woke after sleeping on the idea of an RCBS (Ohaus) 10-10 balance beam.

Now I've read several good personal reports of the GemPro 250 and I have to give it the same consideration.

It just has to be kept on a vibration proof benchtop, somewhere kept clear of anything else, and powered on full time to get best use of it. And kept under a decent dustcover for the 99% of the time it's not being used.

Set it up right the first time it gets powered on and never move it or power it off again, just check and set the calibration every so often.

If the zero drifts between reloading sessions don't just tare the empty pan, consider recalibrating. Zeroing just resets one calibration point, the calibration weights add more. The GemPro 250 comes with a single 308.64 grain weight. At least my Chargemaster comes with two. I warm it up for at least 24 hours and recalibrate every use.

I'd keep a piece of paper in a plastic sleeve next to the scale to keep track of zeros and when it was calibrated. Keeping any record of instrument performance is better than nothing. Helps at work.

Still pretty good value for the $150 range.
 
alinwa said:
Ben, trickle a few kernels on, see how many kernels you need to register a change. (Some of us (well, one of us :) ) believe that a kernel is worth 3-5fps)

al
Click to expand...

I have a Acculab VIC-123, which claims to be sensitive to 0.02gr. I find that a kernel of most powders will move the reading 0.02-0.04gr, depending of course on how bulky the powder is; in other words, sensitive to a single kernel.

There's a gentleman by the name of Scott Parker who will tune your 10-10 to be sensitive to a single kernel:
http://forum.accurateshooter.com/index.php?topic=3330907.0

If that's the case, then the sensitivity of a tuned 10-10 should be finer than +/- 0.1 grain.
 
go read your book again
the ACCURACY is 0.02
THE SENSITIVITY is 0.03
DEFINE "MOST" KERNELS OF POWDER...try n133 try h4227...
mike in co
nhm16 said:
I have a Acculab VIC-123, which claims to be sensitive to 0.02gr. I find that a kernel of most powders will move the reading 0.02-0.04gr, depending of course on how bulky the powder is; in other words, sensitive to a single kernel.

There's a gentleman by the name of Scott Parker who will tune your 10-10 to be sensitive to a single kernel:
http://forum.accurateshooter.com/index.php?topic=3330907.0

If that's the case, then the sensitivity of a tuned 10-10 should be finer than +/- 0.1 grain.
Click to expand...
 
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