RCBS Chargemaster problem

L

lvgolfer962

Sergeant
Full Member
Minuteman
May 8, 2012
231
0
44
#1
I've been running this unit for a few years and its worked great up until recently(or i never noticed it until now).

Most of the time I will load in lots of 200-250 rifle rounds to keep everything the same. Over the past few months I have been throwing one extra charge and will use it to make sure the scale is reading the same when i start loading another lot of ammo.

My load is 41.6 and when i start the machine up(re calibrate it every time) the charge i saved from the last session is reading 41.3 or 41.5 most of the time????
I've even pulled apart some rounds that were supposedly loaded up at the 41.6 and they all read low.


Things ive done
cleaned and de-static-ed the unit
calibrate the scale
let it warm up before loading
Had friends throw charges on there dispensers and see what mine read vs theres

Is this thing messed up or is there something im missing?
 
#2
The best $40 I ever spent was buying the set of RCBS check weights. I'll throw a handful charges and then double check the scale and I do that over and over over the course of loading, this method has saved me from any drifting a good number of times. Using an old thrown charge is a horrible baseline method.

It could be messed up too and set of check weights will show you if it is.

P.S. Buy some check weights

P.S.S. Get some check weights
 
#5
Funny... High Binder should know that:

http://www.snipershide.com/shooting/snipers-hide-reloading/241898-imr-4064-a.html

High Binder said:
I agree with what you said here. Personally I don't think there's much benefit from loading to such a hyper degree of accuracy because lets be honest none of us can capitalize on it. There are simply too many other factors that come into play in this arena but it obviously matters to hlee otherwise he wouldn't be trying and posting this thread. My responses in this thread have been to that end even though I think it's a fool's errand but chiming in and telling him to go to a CM1500 isn't helping him at all for the reasons I stated several times in this thread and are in fact counter-productive to his end.

Now personally, I run a CM1500 and a POS Lyman1200 for my auto-chargers because they serve my purposes.
Click to expand...
 
#6
put a piece of cotton or something into the funnel to stop any powder from coming out. Then remove the black plate the metal dish sits on. Is there any power inside on the scale? If there is get one of those cans of air and gently spray it into the area. I accidentally dropped some in there a while back and my charges were off. When I cleaned it all charges were spot on. I used check weights and I also use a beam scale for verification.
 
#7
918v said:
The CM comes with check weights.
Click to expand...

mijp5 said:
Beat me to it, it comes with 2 50gram check weights
Click to expand...


No, those are "Calibration Weights and weigh over 700 grains each. A set of "Check Weights" usually consist of smaller weights in 20, 10, 5, 2, 1, and .5 grain sizes. This allows one to "build" a set of weights that closely approximate your charge weight and tell you if your scale is accurate at that part of it's range.

The "Calibration Weights" are to merely calibrate the sensor at 0, 50 grams, and 100 grams. If there is an issue with linearity then you can have errors in loads of 40 grains or so.

I find that my Chargemaster does best if I just leave it turned on. I've had mine for over 5 years now and it's only been turned off by me twice when I moved it to different locations. The only other times it's been turned off is if the power company interrupts power.

Leave it turned on, make sure the nuts on the bottom are tight, and also make sure the area under the black "pan support" is clean. I blow mine out periodically with an old "squeeze bulb" device that came in an ear wax removal kit.

Before I start loading I determine the charge weight, then add the check weights to the pan that are closest to the weight I want. Example: I want to load 43.5 gr of Varget so I put the two 20 gr weights, a 2 gr, a one gr, and a .5 gr weight on the pan. If it doesn't read that amount then I calibrate. If it does, no calibration necessary. I round off to the nearest .5 gr if my desired load falls between any two "whole numbers". Again, if the check weight total is the same as what's indicated then no calibration required.

I basically don't care if a scale reads a perfect 0, 50 grams, or 100 grams, when I want a perfect 43.5 gr.

Same goes for my beam scale. I only care what it indicates at the desired weight and don't fart around a lot with "Zeroing on an empty pan".
 
#10
918v said:
The CM1500 self zeros the empty pan.

How much variance have you seen using the check weights?
Click to expand...

The pan can hardly be considered a check weight as it is of an unknown weight and any drifting off of zero wouldn't be seen with just the pan as the pan is part of the drifting. Using fine check weights (not gross CALIBRATION weights) is central to consistency. With check weights I've seen a few tenths variation from 'zero' that I wouldn't have seen if I were relying on the pan (do you need help with the math on that 918v? I know it's not your strong suit).
 
#11
What's a few tenths?

The purpose of the CM1500 is to dispense powder. It does not matter if it dead on accurate as determined with a calibrated check weight. It does not matter if a 41gr check weight weigh 41grs or 40.8grs. That level of accuracy is good enough for reloading.

What matters is consistency as evidenced by the lack of drift. After calibration, my CM1500 will show one weight for the pan but over time the pan will appear up to three tenths heavier as evidenced by the readout when I remove the pan. But the unit self zeros it. So each charge starts off from zero.

Now, I can take a 53gr Vmax bullet that weighs 53.0grs after calibration and weigh it months later when the pan has gotten .3grs heavier and it will still weigh 53.0grs. I have checked this time and time again. The CM1500 is consistent.

As long as it is consistent, you don't need check weights closely matched to your charge weight. If that were important the manufacturer would provide calibration weights in the intended range of use.
 
#12
Binder's right, check weights are the only route, even with a beam scale.
OP, these CM's drift, bad, a guy needs to calibrate a number of times, on diff days, and determine pan weight, then when loading watch the readout when you remove the pan, to make sure it's the same always, if it's drifting, you need to recalibrate. Sometimes, if the pan doesn't go back to zero, you can zero it and resume, but there is positive and negative, if it's showing neg, and you re-zero, now you're .02gr off. but that will show when you remove the pan if you have a designated pan weight.

And don't think these things don't go bad, I have 2 sitting here, I think they're #'s 3&5, but usually when they do go tits up, it's quite apparent.

And some clowns will suggest comparing the charge weights on a beam scale??? Without check weights do you really have a clue as to which scale is right?
 
#14
918v said:
What's a few tenths?

The purpose of the CM1500 is to dispense powder. It does not matter if it dead on accurate as determined with a calibrated check weight. It does not matter if a 41gr check weight weigh 41grs or 40.8grs. That level of accuracy is good enough for reloading.

What matters is consistency as evidenced by the lack of drift. After calibration, my CM1500 will show one weight for the pan but over time the pan will appear up to three tenths heavier as evidenced by the readout when I remove the pan. But the unit self zeros it. So each charge starts off from zero.
Click to expand...

Sorry pal, but since you've shown up here in the reloading section, you've passed out some of the lamest advice to date. If your pan weight is varying .03gr and zeroing itself, to me you may be off by .04. These CM's are a great loading tool, but as far as being a precision tool, they're a POS, pure and simple.

I'm not looking to fight with you on the forum, but.
 
#16
milo 2.0 said:
If your pan weight is varying .03gr and zeroing itself, to me you may be off by .04.
Click to expand...

I can zero the scale without the pan and the Vmax will weigh 53.0grs.

I can zero the scale with a Dillon pan and the Vmax will weigh 53.0grs.

I can zero the scale with a RCBS pan and the Vmax will weigh 53.0grs.

I'm not weighing the pan.

I'm determining the difference in weight between the pan and what's inside.

The pan is automatically zeroed out prior to every charge.

The actual charge weight is not relevant as long as your CM1500 is being used to throw it for your rifle. There is more variance in powder lots, brass, and the weather to make the actual charge weight as important as you are making it out to be.
 
#17
Thanks fellas

Never knew about the check weights, im going to order me a set today.

Im sure i have some powder down in the scale part, i will blow that area out as well
 
#18
My RCBS pan weighs 335.5grs after calibration. I have seen it weigh as much as 335.8grs.

335.8/335.5= less than one tenth of one percent error.

A 41.5gr charge weight multiplied by this error will weigh 41.54grs.

Big fucking deal!
 
#19
918v said:
My RCBS pan weighs 335.5grs after calibration. I have seen it weigh as much as 335.8grs.

335.8/335.5= less than one tenth of one percent error.

A 41.5gr charge weight multiplied by this error will weigh 41.54grs.

Big fucking deal!
Click to expand...

Damn, you're clueless.. How do you know what your weights actually are (the point of this thread) if you don't have check weights to check against? The method you posted above doesn't in any way capture the drift you may or may not be seeing. Simply weighing your pan and using that as your check is as stupid as you are because (as you've been told many times now), you have no idea how much your pan should weigh (a standard). Do us a favor and stop giving out bad advice, you're polluting this forum with your bullshit and you have shown time and again that you are far from the "expert" you make yourself out to be.


918v said:
Big fucking deal!
Click to expand...

Obviously not to you but there are a lot of people on here who do care and do strive for precision.
 
#20
High Binder said:
Damn, you're clueless.. How do you know what your weights actually are (the point of this thread) if you don't have check weights to check against? The method you posted above doesn't in any way capture the drift you may or may not be seeing. Simply weighing your pan and using that as your check is as stupid as you are because (as you've been told many times now), you have no idea how much your pan should weigh (a standard). Do us a favor and stop giving out bad advice, you're polluting this forum with your bullshit and you have shown time and again that you are far from the "expert" you make yourself out to be.
Click to expand...

Instead hurling insults, use what little you have in your head and think:

It's not about THE ACTUAL FUCKING WEIGHT.

It's about the CONSISTENCY!!!!

I don't give a fuck about the actual weight of the powder. I'm not selling it for $1860 a kernel. What I care about is the consistency at which the powder is dispensed. I worked up my load. The key term is worked up.
 
#22
918v said:
Instead hurling insults, use what little you have in your head and think:

It's not about THE ACTUAL FUCKING WEIGHT.

It's about the CONSISTENCY!!!!

I don't give a fuck about the actual weight of the powder. I'm not selling it for $1860 a kernel. What I care about is the consistency at which the powder is dispensed. I worked up my load. The key term is worked up.
Click to expand...


You're still missing the point... Here's a clue: As stated many times now, you have no idea what your actual measurement of "CONSISTENCY" is because you don't have a standard with which to base any of your conjecture on. In other words you don't know what anything weighs because you cannot account for drift in your method. Dumbass.
 
#23
For those of you who don't understand what's going on here, this is the problem:

Powder is manufactured in lots. These lots vary in burning rate. They can vary by as much as 5%. This means that a load consisting of 41.5grs of powder which gives 2600 FPS may not give 2600 FPS with the next lot of powder at the 41.5gr charge weight. Therefore, it is important to adjust the powder charge for each lot of powder to maintain your load's accuracy.

The purpose of a powder dispenser is not to weigh powder and give you the exact weight. That's the job of a lab scale that costs $2500. The purpose of a powder dispenser is to dispense powder consistently so that you can accurately reproduce your load. If you work up a load on your RCBS Chargemaster 1500, and the RCBS Chargemaster calls it 41.5grs, then that's your load. Even though the actual weight may be 41.4grs, the Chargemaster calls it 41.5 and will accurately reproduce it every time. It does not matter that it's off by .1grs in actuality because the whole point is to reproduce it consistently. If you throw it today it will be the same as if you threw it yesterday and it will be the same when you throw it next month. All that matters is that your rifle likes what the Chargemaster calls 41.5grs.

And when you run out of this lot of powder, you'll have to adjust for the next lot. What the Chargemaster 1500 called 41.5grs may or may not be what the new lot calls for. So adjust away. You may have to program in an additional .2grs or maybe .1grs less. The Chargemaster will throw it consistently.
 
#24
High Binder said:
You're still missing the point... Here's a clue: As stated many times now, you have no idea what your actual measurement of "CONSISTENCY" is because you don't have a standard with which to base any of your conjecture on. In other words you don't know what anything weighs because you cannot account for drift in your method. Dumbass.
Click to expand...

Look:

The weight of the 53gr Vmax does not change over time. Can you get that through your empty head?
 
#25
918v said:
For those of you who don't understand what's going on here, this is the problem:

Powder is manufactured in lots. These lots vary in burning rate. They can vary by as much as 5%. This means that a load consisting of 41.5grs of powder which gives 2600 FPS may not give 2600 FPS with the next lot of powder at the 41.5gr charge weight. Therefore, it is important to adjust the powder charge for each lot of powder to maintain your load's accuracy.

The purpose of a powder dispenser is not to weigh powder and give you the exact weight. That's the job of a lab scale that costs $2500. The purpose of a powder dispenser is to dispense powder consistently so that you can accurately reproduce your load. If you work up a load on your RCBS Chargemaster 1500, and the RCBS Chargemaster calls it 41.5grs, then that's your load. Even though the actual weight may be 41.4grs, the Chargemaster calls it 41.5 and will accurately reproduce it every time. It does not matter that it's off by .1grs in actuality because the whole point is to reproduce it consistently. If you throw it today it will be the same as if you threw it yesterday and it will be the same when you throw it next month. All that matters is that your rifle likes what the Chargemaster calls 41.5grs.

And when you run out of this lot of powder, you'll have to adjust for the next lot. What the Chargemaster 1500 called 41.5grs may or may not be what the new lot calls for. So adjust away. You may have to program in an additional .2grs or maybe .1grs less. The Chargemaster will throw it consistently.
Click to expand...

OK, that's the first smart thing you've said, and myself and Binder probably wont argue.
The discussion was CM drift and repeatability, was it not?
 
#27
Question:

You think the drift is inconsistent and sporadic? I haven't seen that. My machine stays put. If it says the pan is 335.5grs today it will stay that way for a long time. Today it was 335.6grs all day, even after I calibrated it. It does not drift between charges. And even if it did it wouldn't matter.
 
#28
Hell, the op, lvgolfer bugged out, let's rumble another day.

918, the pic to the left is 6 1/2 year old kid with a hit at 1350 with one of my rifles and ammo. I know how to load accurate ammo, and I know what to do to a rifle to make it accurate, even f I don't build my own.

Also though, I know the limitations of my CM's, and account or adjust for them.
 
Last edited:
#31
milo 2.0 said:
Hell, the op, lvgolfer bugged out, let's rumble another day.

918, the pic to the left is 6 1/2 year old kid with a hit at 1350 with one of my rifles and ammo. I know how to load accurate ammo, and I know what to do to a rifle to make it accurate, even f I don't build my own.

Also though, I know the limitations of my CM's, and account or adjust for them.
Click to expand...

That's great.

Maybe RCBS should make a CM Elite with a GemPro attached.
 
#36
Update

Got my check weights the other day.

Blew out the scale/pan area
its been plugged in and left on for a few weeks
de-staticed with a dryer sheet


Every check weight i put on the scale read true!
Ive reloaded about 400 rounds on it since and have been checking the scale with the weights around every 50 rounds and its been dead on.

So thanks for all the advice and info, my scale is running strong again
 
#38
Another option: I have a check-quarter, a check-nickel, and a check-dime. These are in the range of close enough for me (35-90gr). I weighed them on the CM scale, verified on a balance beam to the XX.Xgr degree, wrote down the weight in sharpie on each one and they sit beside the 50g weights on the unit...
 
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