Let's Talk High Precision Scales

[gng4life]

I used to calibrate scales as part of my job. The problem is, the higher the precision (eg more decimal points) the more external factors affect the readings. When air pressure changes, temperature changes, even humidity can affect readings. Is an air conditioner or heater in the house running, setting up smal drafts that cause unstable readings. That is why on supper precise scales the pan is usually enclosed with a clear plastic box of some kind. Even static electricity has a huge affect. At some point it is just going to be more trouble to try to get more accurate readings than it is worth.

Good info here, thanks for sharing. Don't you want more accuracy so the variation isn't as wide? If you keep it in the same room, almost same temperature, control any air currents, shouldn't you get more accurate and consistent readings?

Are you reloading and measuring each and every charge by hand or are you just verifying charge weights from a powder drop mechanism on a machine?

Me?? Heck no, I weigh at the beginning of a session, one more around 100 rounds and that's it. I might do one more check at the end of a session. I am just looking for a digital scale that is accurate and consistent. I have had three digitals and granted they weren't very expensive but they were horrible. The OP is looking for the something a little more precise and that can withstand the temperature changes.

[Bkreutz]

I don't mind a bit of inaccuracy when I'm loading a mid range 9 minor load, but when I'm at the ragged edge of 9 major loads, I don't want variations of more than 0.1 of a grain (0.0x accuracy isn't needed IMO).

[mpeltier]

I used to calibrate scales as part of my job. The problem is, the higher the precision (eg more decimal points) the more external factors affect the readings. When air pressure changes, temperature changes, even humidity can affect readings. Is an air conditioner or heater in the house running, setting up smal drafts that cause unstable readings. That is why on supper precise scales the pan is usually enclosed with a clear plastic box of some kind. Even static electricity has a huge affect. At some point it is just going to be more trouble to try to get more accurate readings than it is worth.

Good info here, thanks for sharing. Don't you want more accuracy so the variation isn't as wide? If you keep it in the same room, almost same temperature, control any air currents, shouldn't you get more accurate and consistent readings?

Are you reloading and measuring each and every charge by hand or are you just verifying charge weights from a powder drop mechanism on a machine?

Me?? Heck no, I weigh at the beginning of a session, one more around 100 rounds and that's it. I might do one more check at the end of a session. I am just looking for a digital scale that is accurate and consistent. I have had three digitals and granted they weren't very expensive but they were horrible. The OP is looking for the something a little more precise and that can withstand the temperature changes.

I understand.

I guess my point is (with scales of extreme accuracy) our powder drop system is the weakest link in the measurement of the powder we put in our reloads. We are verifying the amount for safety sake. The scale is simply telling us if the amount is still in the safe zone if you will. the small deviation in 100'ths of a grain is insignificant to safety and/or down range accuracy of our reloads. Theres a plethora of other details more important to down range accuracy than attempting to get the powder measurement any more accurately than your average scale will provide.

Its tantamount to a cat chasing its tail.

[warpspeed]

So does anyone actually think charges in the 0.0X of a grain make a damn difference to anything except mollifying our OCD?

Im glad you said that. Its exactly what I was thinking. Big waist of time and money. IMHO, But with over 40 years of reloading experience what do I know............?

So the idea of seeing that resolution is so that as you trickle powder in one grain at at time you can stop when you want.

[warpspeed]

When using a beam scale waiting for the beam to settle is a pain, but the stupid powder pan swinging (and trying to stop it) is what really drives me mad. I have seen many old beam scales measuring food etc that have a platform onto which the thing to be weighed is placed.

I have yet to see a beam scale that measures in small amounts such as those we need for pistol powder etc that has a platform onto which the powder pan can be placed rather than hung and swinging. Have y'all seen any beam scales like I am talking about (platform rather than hanging)?

I have a couple of different scales that I use based on what I'm weighing.

I use an old Redding #2 beam that has been tuned when I need to weigh a charge that has to be as close to perfect as possible. It was tuned by a gentleman named Scott Parker in Bakersfield, CA. It will indicated the removal or addition of one kernel of powder. The think I like most is that even as it swings a bit, the pointer doesn't move.

[jmorris]

So the idea of seeing that resolution is so that as you trickle powder in one grain at at time you can stop when you want.

My idea in post 23 was to be able to duplicate that resoultion to test out with my "railgun" build to see what the actual difference between "to the kernel" loads with just a volume charge, without spending money I don't have on something I really don't care about.

[dauntedfuture]

Might I suggest that one needs to look at the ES of their ammunition to evaluate if the scale they have works. If the ES is low then your scale is proper. I don't think that you are going to see effects on target of thrown vs weighted or a .2g spread until you get past 300 yds or so. What you are going to have to rely on is looking at the ES and to a lesser extent SD numbers. My ES and SD is a little higher then what I might like it to be. I intedd to buy a new scale when I get back, I have an old basic RCBS at the moment, and what I don't know is that if I weight 100 charges and they all say 24.2, are they all really 24.2 or is it more like 24-24.4. Years ago I bought a cheep electronic scale and it might have cost me a natl championship, after I got home and pulled bullets, me meticulous weighted powder charges were +- .3g on my balance beam scale.

My plan when I get my new scale is to load 10 rounds with powder weighed on old and new scales and shoot them all over a crono and see if there is a difference. Speed and convenience are also a factor with a new scale and it is easier to read an electronic scale. To date my electronic scale has only been reserved for weighing bullets and brass.

[gandog56]

I used to calibrate scales as part of my job. The problem is, the higher the precision (eg more decimal points) the more external factors affect the readings. When air pressure changes, temperature changes, even humidity can affect readings. Is an air conditioner or heater in the house running, setting up smal drafts that cause unstable readings. That is why on supper precise scales the pan is usually enclosed with a clear plastic box of some kind. Even static electricity has a huge affect. At some point it is just going to be more trouble to try to get more accurate readings than it is worth.

Good info here, thanks for sharing. Don't you want more accuracy so the variation isn't as wide? If you keep it in the same room, almost same temperature, control any air currents, shouldn't you get more accurate and consistent readings?

That IS the problem with super accurate scales. Getting two readings in a row that agree. All the external factors that can affect the raedings make it hard to do in a home environment. I calibrated them in a total temperature and humidity controlled lab. We had to monitor them both with chart recorders. Neither could vary by a couple of digits for over an hour time or you had to stabilize for 72 hours before you could start calibrating them again. Is your house that good? Like I said, the higher the accuracy, the more external factors can alter your readings. At what point do the changes negate the accuracy?

Edited May 23, 2015 by gandog56

[gng4life]

I guess it depends on what you mean by "super accurate scales". Going into the hundredths for grain readings doesn't sound like super accurate territory but I don't know for sure. I still plan on getting one and doing some tests of my own just to see what happens. Thanks for the info.

Sent from the range

[jmorris]

This one would fit my definition of "super accurate", measures to he kernel each time.

[BoyGlock]

My scale is not high precision but Im confident my loads are precise and accurate enough. Read sometime somewhere here about this simple method and made it my routine when making new loads or checking my powder setting:

I put 10 throws to the scale pan and it must read 10x my desired load. If my intended load is 7.20gr the scale must read 72.0 grains in 10 throws. A deviation from 7.20 that does not register in single throw readings, say 7.21, 7.25, 7.18, 7.16 etc will be magnified 10x and will surely show in the readings for the 10 throws. If you wish to be more precise than that make it 20 throws or 30 or whatever you wish

[gandog56]

Aww what the heck. I use the Hornady auto dispensor/scale. Every charge gets weighed out automatically. If it happens to go over what you dialed in, there is an audible alert and overload indication on the scale display.

[gng4life]

Wow, that's crazy! Yeah, nothing like that. I just a very accurate digital scale that works. Every one I have purchased seemed to fail not long after getting it. By getting that one at UniqueTek, it seems sturdy and plenty accurate for what we do so I'm going that route unless someone convinces me that it sucks or breaks often.

[427Cobra]

I use a el cheapo digital to check my Dillon powder measure, but for precision rifle I have the holy grail, a Gen 2 Prometheus, it wasn't cheap, and totally worth it, at 1780 yards my vertice was cut by 2/3rds, both my old school Chargemaster and Gen 1 Prometheus are great scales/dispensers, but the Gen2 Prometheus will dispense to the kernel every 8-10 seconds, and it shows on target, and chronograph, when I miss a target, and I do, it's not because of my ammo, rifle, it's me, so if we are talking absolute presicion, get a great scale, and don't waste your money on a GemPro.......

[rdinga]

Cave man scales...rcbs chargemaster and Brian Enos version of Gem Pro....backed up by RCBS balance beam. For how I shoot this works fine. Dont think I will need to lease a prometheus to weigh WSF for my Glocks.

[Bob DuBois]

Use a Dillon beam scale to set weights and a $20.00 check weigh scale at the bench. Spent my time working on the powder measure.

Removed the plastic tube and the bars. Polished the inside, funnel section till mirror finish, Lightly polished the bars.

Cleaned up the powder funnel and polished the inside. Now my Chrono spreads are closer because the powder drops are close. Test was

loading Solo 1000, a light flake powder that doesn't meter well, now it drops the same charge every time.

Also cut a circle out of a piece of 1/8th metal screen using the powder top as a guide. Placed the screen below the plastic

tube when assembling. There's a powder adjustment knob and bolt on E Bay for $12.00 installed and am very pleased.

On the top bar in the powder measure, if you notice a little slop when assembling remove the top bar, put a strip

of clear packing tape on the top cut off excess with a razor blade reassemble and check operation is still smooth.

the top bar in pistol calibers does not move.

The little Mid Way scale is dead on with my Dillon beam scale, ops we are working on a Dillon powder measure.

[Beacon22]

I just bought a Sartorius Entris 323-1S. It is not a Strain Guage scale like the GemPro 250 or the Ay-123. Strain Guage scales are just not reliable.

The Entris 323-1S uses Magnetic Force Restoration. I spent slightly over $750 for the scale including an ASTM Class 1, 200 gram calibration weight.

I am blown away at the accuracy, repeatability and linearity of this scale. A lot of the long range shooters use this scale which replaced the Sartorius GD-503.

I def didn't plan on spending this kind of money on a scale but after using a bunch of different digital scales first hand (no, not just reading the specs) and comparing the results I came to the realization that with certain types of equipment you truly get what you pay for and scales fall in that category for sure.

Now to get my Dillon powder measure to drop this accurately!!