Chargemaster Scale Better Than Display?

[CharlieNC]

For mass loading I purchased a Chargemaster. As others have reported the charges weighed on a different scale are usually much less that the +/- 0.1 resolution of the display. My knowledge of these types of systems goes back 35 years during the transition from analog to digital devices so I am not up to date. I wonder if the sensitivity of the strain gauge and the digital logic is better than what is shown on the display, as it is likely that all these may be separate devices. Weighing individual powder kernels I have learned that the display is for discrete 0.1 increments and does not appear to round up or down, and this does not jive with the charges I have weighted on a scale with finer resolution which indicate the unit is more precise than the display. I must say the performance is much better than I expected. Anyone have any insight on this?

 

[powderbrake]

I have used my Gem Pro 300 to check the output of my Chargemaster, and it generally runs within +- .05 grains of the setpoint

 

[DevlDogs55]

Something I've started doing is setting the Chargemaster to 33.8gr when I want to throw a 44.0gr charge. I trickle up to 44.0 and stop the second it hits 44.0. I can manually trickle one or two kernels at a time.

I tried this method after seeing a YouTube video of this method being tested with a GD503. I don't have a GD503 myself, but was able to verify that I was getting more accurate throws, as shown in the video, while borrowing a friend's 503.

 

[mikecr]

That presented in the video shows the CM system can be accurate beyond indicated.
Once he used the scale better, and learned about it's best trickle response, he would no longer need the higher resolution validation(which goes beyond individual kernel weights anyway).

The Omega trickler is better, but the CM's trickle can be improved well enough for shown performance here.
I know, because I've learned to operate my CM to the kernel, using it's own trickling(modified).

 

[CharlieNC]

These types of experiences are why I'm wondering.....

 

[ranger3]

That presented in the video shows the CM system can be accurate beyond indicated.
Once he used the scale better, and learned about it's best trickle response, he would no longer need the higher resolution validation(which goes beyond individual kernel weights anyway).

The Omega trickler is better, but the CM's trickle can be improved well enough for shown performance here.
I know, because I've learned to operate my CM to the kernel, using it's own trickling(modified).

How did you modify trickling?

 

[Homerange]

How did you modify trickling?

You can't get accurate trickling without first adding dispensing a bush/insert or a MacD straw mod to the dispensing tube.

Then you have to mod the dispensing parameters by stopping the main fast/medium earlier and leaving a little more of the charge to be trickled. It's done by adjusting the system parameters from within one of the setup menus, info on this is in a # of threads.
Some settings are mentioned in this thread:
http://forum.accurateshooter.com/threads/rcbs-chargemaster.3922567/

 

[mikecr]

How did you modify trickling?

Programming won't adjust trickling speed, just where it begins. I can adjust my trickling for best scale settling/accuracy per powder with a potentiometer. This doesn't affect high/mid speeds but gives very good adjustment over trickle speed.

 

[Homerange]

Programming won't adjust trickling speed, just where it begins. I can adjust my trickling for best scale settling/accuracy per powder with a potentiometer. This doesn't affect high/mid speeds but gives very good adjustment over trickle speed.

Mike, does it soften the little twitches when in trickle mode ?
Do you change the pot setting for different powders ?
Could you conceivably leave at just one setting or place a fixed resistor in series with the motor if you didn't want to mod the case ?
Thanks for sharing this.

 

[Twoboxer]

Programming won't adjust trickling speed, just where it begins.. . .

There are 3 parameters that purportedly adjust speeds:

W_F (200) Rotation for Full speed
W_M (100) Rotation for Medium speed
W_S (036) Rotation for slowest speed

The parameters are a single byte in length, holding numbers 0-255. The paranthetical numbers are the factory settings. Clearly the smallest number, ie "036", is the lowest speed. So by substituting a "001" (or perhaps "000") you should be able to slow the trickle speed itself.

I've done that, and there was no noticeable change in performance. YMMV.

ETA: My finding may be due to High Speed and the final trickle speed actually being fixed. In that case, the W_S parameter actually may refer to the speed used in the range just prior to switching to final trickle.

 

[mikecr]

Mike, does it soften the little twitches when in trickle mode ?

Yes

Do you change the pot setting for different powders ?

Yes

Could you conceivably leave at just one setting or place a fixed resistor in series with the motor if you didn't want to mod the case ?

No, that wouldn't work. This is about calibrating the final trickle speed for dropping of a particular powder.

You can learn to read the scale and see single kernel drops creep into desired. This is not so fast to overcharge, or so slow to lock onto undercharge. Then disturb the pan and watch the scale go back into solid lock on desired. If a re-reading of the charge is slow to lock dead nuts on, pour out the charge and do another, and another. This is where my speed adjustment comes into play. When it's right I won't have to mess with the adjustment again for that powder & session.
Still need to disturb the pan and witness a good reading for every charge.

 

[T-shooter]

For mass loading I purchased a Chargemaster. As others have reported the charges weighed on a different scale are usually much less that the +/- 0.1 resolution of the display. My knowledge of these types of systems goes back 35 years during the transition from analog to digital devices so I am not up to date. I wonder if the sensitivity of the strain gauge and the digital logic is better than what is shown on the display, as it is likely that all these may be separate devices. Weighing individual powder kernels I have learned that the display is for discrete 0.1 increments and does not appear to round up or down, and this does not jive with the charges I have weighted on a scale with finer resolution which indicate the unit is more precise than the display. I must say the performance is much better than I expected. Anyone have any insight on this?

I don't own a Chargemaster but Hornady's version, Autochager. They are similar in operation and are suppose to have a +/- .1 accuracy. I have learned not to trust it and use it to get close and then trickle up to the desired charge. May be ok for plinking ammunition but not anything approching precision. For instance I ran 29 loads on the Hornady set to 40 grains using Varget powder and I also use the straw trick in the discharge tube which helps. The maximum spread was .36 grain. I checked using a milligram electronic scale which is consistent to +/- .02 grain. Out of 29 loads it only showed an overcharge once but going over five times here without a warning. Here is a a list of the results with the Autocharger stopping on 40.0 and how many times.
40.18 (1) grains
40.10 (1)
40.04 (3)
40.02 (2)
40.00 (2)
39.98 (4)
39.96 (6)
39.94 (1)
39.92 (3)
39.90 (3)
39.88 (1)
39.86 (1)
39.82 (1)
Not exactly accurate by no means. From this simple test, the display could be +/- .18 grain. I did try loading with CFE223 spherical powder and it metered more accurately but still had a 2/10 spread.

 

[ranger3]

I've never had that with the chargemaster, it always warns me when it does an overcharge. I also haven't had over-under throws by more than .1 grain, knock on wood anyway. I'm sure better results are possible, but with a hefty price tag as well.

 

[CharlieNC]

Mine come in at +/- .06gr unless the over or under charge warning activates.

 

[HVYDOC]

An APC line conditioner & led lighting helped my CM1500 & balances more than anything else I've tried. Going to a smaller bushing in the CM because I still get an occasional over charge when a pile falls out at the end of a charge. But a clean 120 volt input keeps in in calibration.

 

[JMMontgomery]

Check this out....it worked for me.

https://www.primalrights.com/articles/re-programming-rcbs-chargemaster-combo

 

[savagedasher]

Just put it on D.C. Battery power. Larry