Weighing In, Scale test.

[Clayne_b]

In this test we used the Denver instruments APX-203 scale for a baseline


Scales to be tested are,

RCBS ChargeMaster 1500


Hornady Lock-N-Load Auto Charge


RCBS Powder Pro Digital Scale


Lyman 1000 XP Electronic Powder Scale


RCBS Model 1010 Magnetic Powder Scale


RCBS Model 505 Magnetic Powder Scale




Checked the weight of a 168gr Berger bullet, 87gr Hornady vmax, and a 250gr check weight

Here is what the weight was on the APX-203 Used as a baseline.
168.16
87.38
250.02

RCBS ChargeMaster 1500
168.1
87.4
250.00

Hornady Lock-N-Load Auto Charge
167.9
87.4
250.00

RCBS Powder Pro Digital Scale
167.8
87.2
249.7

Lyman 1000 XP Electronic Powder Scale
168.1
87.4
250.00

RCBS Model 1010 Magnetic Powder Scale
168.03
87.3
250.0

RCBS Model 505 Magnetic Powder Scale
168.2
87.3
250.1

Now on to the RCBS ChargeMaster 1500
Hornady Lock-N-Load Auto Charge
RCBS Uniflow Powder Measure, thrown only no trickle

10 charges with the target load of 43gr checked on the APX-203

Hornady Lock-N-Load Auto Charge, with Benchmark
43.16 17sec
43.16 20sec
43.24 20sec
43.46 20sec
43.20 20sec
43.12 18sec
43.12 20sec
43.26 18sec
43.12 19sec
43.16 20sec
ES .34gr
SD .098gr

RCBS ChargeMaster 1500, with Benchmark
42.94 24sec
43.06 19sec
43.04 14sec
43.06 18sec
42.96 11sec
42.98 20sec
43.02 17sec
42.94 20sec
43 20sec
42.96 14sec
ES .12gr
SD .075gr


RCBS Uniflow Powder Measure, with Benchmark
42.98 1sec
43.04 1sec
42.92 1sec
43.24 1sec
43 1sec
42.82 1sec
42.86 1sec
42.90 1sec
42.96 1sec
42.98 1sec
ES 42gr
SD .110gr


10 charges with the target load of 43gr checked on the APX-203

Hornady Lock-N-Load Auto Charge, with AR-Comp
43.24 18sec
43.36 22sec
43.32 19sec
43.16 18sec
43.04 20sec
43.20 17sec
43.44 19sec
43.28 20sec
43.10 20sec
43.22 21sec
ES .40gr
SD .114gr

RCBS ChargeMaster 1500, with AR-Comp
42.98 16sec
42.92 20sec
42.92 19sec
42.90 24sec
42.92 13sec
43.02 16sec
42.96 26sec
42.96 21sec
43.04 20sec
43 20sec
ES .14gr
SD .045gr

RCBS Uniflow Powder Measure, with AR-Comp
43 1sec
42.98 1sec
43.12 1sec
43.12 1sec
43.08 1sec
42.92 1sec
42.88 1sec
42.94 1sec
42.88 1sec
42.96 1sec
42.98 1sec
ES .24gr
SD .082gr


10 charges with the target load of 43gr checked on the APX-203

Hornady Lock-N-Load Auto Charge, with H-4350
43.8
43.12
43.04
43.16
43.16
43.16
43.22
43.20
43.16
43.18
ES .76gr
SD .198gr

RCBS ChargeMaster 1500, with H-4350
43
42.9
43.02
42.96
43.02
43.04
42.98
42.94
42.90
43.06
ES .16gr
SD .053gr

RCBS Uniflow Powder Measure, with H-4350
42.94
42.88
43.08
42.90
42.96
42.96
42.86
42.96
42.96
42.96
ES .20gr
SD .057gr

Up to this point the RCBS was at factory settings. We then did the McDonald's Straw mod and changed some settings on the RCBS ChargeMaster to make it faster, with H-4350
43.08
43.02
43.08
43.02
43.02
42.96
42.96
43
42.9
43
ES .18gr
SD .051gr

This improved the average time from 20.5sec to 14.4 seconds over a 10 throw average

Here is a video on how to do that.
http://www.youtube.com/watch?v=vbG2Mw4b4a0&feature=share&list=UUJpcXEbKcTfLOG_NsUiyRxg

Testing done by
Eric S
Clayne B

 

[Clayne_b]

bump

 

[mdm]

Your comparison of the scales is interesting. However, you are using items of unknown weights for the comparison. Rather than using bullets, which will vary in weight, it would be more useful to use check weights.

 

[Clayne_b]

Used one bullet that was a 168gr and one that was 87gr, not a separate bullet for each scale

 

[mdm]

Used one bullet that was a 168gr and one that was 87gr, not a separate bullet for each scale

I assumed that. However, how much do your 168 gr and 87 gr bullets really weigh? When making comparisons between scales you need a control. That control should be an actual check weight of known weight. Bullets can vary in weight enough to not be a good comparison. If the object you are using is of unknown weight, what you are showing is which scales come closest to agreeing with each other, not which scales are giving the most accurate measure.

 

[Clayne_b]

168.16
87.38

according to the APX-203

Look into that scale....

 

[au_prospector]

laughing, I think what he means to say is VERY UNLIKELY your bullets weigh exactly what the box says they do. Your experiment supports that notion as your CHECK WEIGHT is very precise at 250.0 grains pretty much regardless of the scale, however the bullets will and do vary because they are not made to exact tolerance.

Would be even more useful if you experimented in the 5-10 grain area as well as the 30-60 grain area as 250 grain powder charges are not realistic. Your method seems good and I do like you sharing this information, much appreciated.

 

[mdm]

My reading skills are suffering today. I completely missed the 250 gr check weight.

 

[LiveLife]

Would be even more useful if you experimented in the 5-10 grain area as well as the 30-60 grain area as 250 grain powder charges are not realistic.

I agree. I use digital scales to sort my bullets by weight and it is much faster than beam scale but I am sorting to the nearest 1 grain, not 0.1 grain.

For more practical usable comparison in the 0.1 grain range, I would prefer to see smaller powder charges of 4.0 - 5.0 grains with scales verified by 4.0 - 5.0 grain check weights.

One test I use to check sensitivity of scales is weighing 1/4" x 1/4" of thinner copy paper. My two Ohaus 10-10 scales would detect and measure one piece of paper but the cheaper digital scales would not detect and measure until 2-3 pieces were placed and barely read 0.1 grain.

Thanks for doing the comparison test and keep us posted.

 

[Reloadron]

Thank you for what was a time consuming effort. However, not to critique but I see a few small problems.

In this test we used the Denver instruments APX-203 scale for a baseline

So would the scale APX-203 then be considered the legal truth or would the test weight you used be considered the legal truth? One of the two needs to be the standard to which everything else is compared.

I read the operators manual for the APX-203 scale and while informative they don't really mention the actual uncertainty of the scale, the specifications cover Weigh Range, Readability and Linearity but do not actually mention uncertainty or what the accuracy is when calibrated using their methods for calibration.

So what is the actual legal truth? The check weight or the scale and if we choose one or the other how do we really know?

Really matters not I guess because any of the errors noted won't come in light of the needed uncertainty of the test instruments (the scales tested).

For the most part just about all scales aimed at the hand loading community have a resolution of .1 grain and those that specify it an uncertainty of +/- .1 grain. That has always been considered adequate for hand loading purposes. A good scale and a good set of check weights that do not need to be ASTM or NIST certified is adequate.

Ron