Chargemaster Test

Apollo

Apollo

Jason Stanley
Hello all. Our school had some really good fortune lately. A local limestone company donated a Mettler Toledo AG104 lab scale to our school's science department. (Very much appreciated!) This scale was certified to .0001 grams in Jan of 2012. If that isn't cool enough, they called me to accept the delivery. The person delivering it would not be able to deliver it until 7 pm. I asked him if he would just stop by my house and I could take it to school on Monday.:cool:

Well Geez...I can't just let it sit there...so I decided to test my Chargemaster against this scale. The main thing I wanted to know is; does the accuracy/precision of the scale change based on how much powder is in the hopper? A 2ndary item would be; how precise is the Chargemaster? Attached are the results. Yes, I realize 2 sets of 10 is not a very big sample, but it proved enough to me. Plus, I have coyotes to shoot and brass to make.

2 main conclusions that I am now hanging my hat on:
1. When the hopper is 3/4 full on my Chargemaster; the powder thrown will be accurate and precise enough for the 100, 200 and 300 yd shooting that I do.
2. If the Chargemaster overthrows - do not just pick out powder with your fingers until the scale reads correct.

Does this LITTLE test prove or disprove that the Chargemaster is more/less accurate than a Harrells? NO. I do not own a Harrells - so could not test it against it, plus I have not spent years perfecting my throwing technique.

Not sure if this helps anyone or not, but it did slightly change the way I do things. (especially the picking the powder out on overthrows)

Stanley
 

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Barely over 0.1 grain extreme spread, I could live with that. That's my scales accuracy limit anyway.
 
crap..sorry. Powder was 34.8 gr of H4198. That is my load in my 30BR. Yes, the extreme spread on the 3/4 was lower than the 1/4.
 
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Thank you for testing this! Good On Ya

Now for another opinion..... In view only one parameter is meaningful, the fact that the Chargemaster varied nearly 2 full tenths of a grain in this small test. IME discrepencies of up to a quarter grain are to be expected, routinely, in every run.

All the "mean" and "median" and SD crap is immaterial, it's the ES that matters and the ES I see indicated here in this run is around 40fps. This means exactly nothing to Those Kings Of Bench Rest, the PPC guys, but to the goofballs who tend to shoot things further away than you can see bullet holes with the nekkid eye it's significant :)

Soooo, you've pointed out the conundrum. Scales are a pita at the range, out in the weather where PPC's rule. CM included. AND, the CM offers no real advantage over the thrower.

I still find use for the CM, and my experiments are right in line with yours.

thanks

al
 
I should have added the extreme spread to the initial sheet. The ES for 1/4 full was .1713 gr and the ES for 3/4 was .0848 gr. In only 10 throws each - that is a big difference. I'm going to make sure my hopper is 3/4 or more full when I fill up my vials for matches.

Stanley
 
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Al,
Granted that the samples are small, noting that reservoir fill seemed to influence outcome, and choosing the more favorable 3/4 full gives us an extreme spread of .085, and doing some interpolation after looking up a H4198 load in that range on the powder mfg. web site, it looks more like an ES of 9 fps, based on charge weight spread alone.

Boyd
 
i think al's opinon is off a bit this time...

THROWN charges are not this consitant.......

CHARGEMASTER is very good for a short range shooter with n133..as it is a bunch better than thrown, and n133 seems to have a large soft/sweet spot...so the cm works at short range.
thrown sucks in comparison....people get away with thrown in short range because of the characteristics of n133....not becuase of the excellence of the thrower.



when one moves to long range..i do not believe either are the best tools available...

thanks for the test....

mike in co
 
My Chargemaster did not come with a "baffle"(sp). I notice on most throwers they have one. Can't be that hard to make.... That might do the same thing in a Chargemaster as it does on a thrower. Anybody here from RCBS? Am I even close to being on the right track?

Stanley
 
What has always bothered me

and why I have weighed charges for years is, we demand ultra accuracy when our rifles are put together. There are always folks who are trying to improve ignition or make rifles track better or any other apect one can thing of yet many folks are satisfied with deviations in powder charges. There are plenty of respected folks who accept this but I have never been able to. I just don't get why some folks are willing to chance leaving something on the table if they don't have to. I hae always been able to see very small differences in powder charges, even one tenth, in the testing i have done and why I have tried to make my ammo as precise as I can. I have wondered as well how muh better the shooters who are better than I would shoot with perfect ammo. ( I'm a 100-200-300 yd shooter) Perhaps there would have been more 250-25's shot or more zero groups.
 
careful peter, you will upset the lemmings.....

mike in co

Pete Wass said:
and why I have weighed charges for years is, we demand ultra accuracy when our rifles are put together. There are always folks who are trying to improve ignition or make rifles track better or any other apect one can thing of yet many folks are satisfied with deviations in powder charges. There are plenty of respected folks who accept this but I have never been able to. I just don't get why some folks are willing to chance leaving something on the table if they don't have to. I hae always been able to see very small differences in powder charges, even one tenth, in the testing i have done and why I have tried to make my ammo as precise as I can. I have wondered as well how muh better the shooters who are better than I would shoot with perfect ammo. ( I'm a 100-200-300 yd shooter) Perhaps there would have been more 250-25's shot or more zero groups.
Click to expand...
 
2 main conclusions that I am now hanging my hat on:
1. When the hopper is 3/4 full on my Chargemaster; the powder thrown will be accurate and precise enough for the 100, 200 and 300 yd shooting that I do.
2. If the Chargemaster overthrows - do not just pick out powder with your fingers until the scale reads correct.

Stanley[/QUOTE]

Help me out on this. Why do you not pick kernels of powder out with your fingers until the weight is right?
I guess this may be a dumb question, but if you've addressed it I must have overlooked the answer.

Rick
 
the system is not sensitive enough...
you need to pick ip the pan and put it back down EVERY TIME YOU CHANGE THE AMOUNT IN THE PAN....
(SAME AS A BEAM SCALE..MOVE THE BEAM EVERY TIME YOU REMOVE OR ADD WEIGHT)

mike in co

Greyfox said:
2 main conclusions that I am now hanging my hat on:
1. When the hopper is 3/4 full on my Chargemaster; the powder thrown will be accurate and precise enough for the 100, 200 and 300 yd shooting that I do.
2. If the Chargemaster overthrows - do not just pick out powder with your fingers until the scale reads correct.

Stanley
Click to expand...

Help me out on this. Why do you not pick kernels of powder out with your fingers until the weight is right?
I guess this may be a dumb question, but if you've addressed it I must have overlooked the answer.

Rick[/QUOTE]
 
Greasy finger, disturbing the load-cell. Just throw it back and have it charge again.


I'm getting ±0.05 on my Sartorius (ie 0.1gr ES). The CM shows the actual wait after it beeps and says what number that was. If it is over/under I toss it back. I've got two CMs next to each other and calibrate before using them together for the same batch, same ES using both, so I'm getting a good spread.

- I have a small alu pipe with inner threads stuck into the original trickler pipe that slows down the process but makes it a lot more consistent.
- I rezero after 30-40 rounds
- I let it warm up for a half hour or so before using them.
- I've got a mains filter in front of it to make sure there is no HF coming in.
- Turn of your cell-phones etc when loading, my Sartorius goes nuts when I have it on and am near it.

Super devices, can't imagine reloading with those balance scales that keep sticking and changing.
 
Hi Rick. Previous to this little test, when the Chargemaster would overthrow (reading after beep and thrown number) I would simply pick out a pinch and throw it in the trash can until the desire amount was reached. During my test this happened, and so I did what I have always done. When I put the pan on the lab scale it was WAAAAY off. (I did not include that in my test data, but the lesson was learned). From now on - if it is low or high, I'm just going to dump it back into the hopper or turn that loaded round upside down and use it as a fouler.
 
The ES of thrown charges, with a given measure, and setup, depends on powder grain size and shape, as well as technique. While one may speak with authority as to what his abilities are, with a given powder, he has no way of knowing if he is as good as someone else, who may have discovered a better technique, and practiced enough, to give repeatable results. With decent technique, 133 can be thrown to an ES of .3gr. With excellent technique one can get very close to .2. (Some say better.)For the new Canadian powders, and surplus 8208 hitting .2 ES and better is not difficult. At some point the other factors involved in real world 1-200 yd match shooting, various combinations of other factors make such small variations in powder charge get lost in the noise. Some of the current, recently shot unlimited aggregate records were shot with thrown charges. 133 is not the most forgiving of powders. That is why so many years of effort have been put into the effort to recreate the lot of surplus 8208 that is known as T powder. All in all, the main reason that I don't have a chargemaster is that I have seen so much excellent shooting done without one, and that I already have more to haul to the range than I like. If I were shooting at top level, I would probably use one, but I am not. In my case, the "noise" that minor charge variations could be a lot less. The only fix for that is trigger time.
 
I did a test once on a Harrel measure between SP7 (very fine ball powder) and N140. The N140 gat 0.4gr spread, the SP7 got 0.05gr spread as it was so fine it was like water and no grains were ever stuck/cut. With measures the shape/size and technique are big factors indeed. Things like always tapping the handle at the bottom or different speeds while throwing cause changes in weight.
 
Maybe I'm just a little stupid today (or always according to many). I can understand how the level of powder in a measure can affect the thrown charge, but have a little difficulty understanding how the level of powder in the "trickler" can have an effect on the weight of powder dispensed onto an electronic (or any other) scale. Any theories are heartily welcomed.

Admittedly the scale on the Chargemaster doesn't hold a candle to a Mettler or Sartorius lab scale, but since I retired I don't have access to either of them or the funds to purchase one either I'm stuck with the Chargemaster and its scale. I'd also be willing to bet that I can't throw a series of charges with any of my measures (Redding 3BR, BR30, or Harrell's) with any but the finest ball type powders. Maybe it's old age and a naturally high level of uncoordination on my part.
 
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