royinidaho
Well-Known Member
I don't recall my ChargeMaster beeping. Its been a year though since I've used it
Heck's fire, maybe I can't hear that frequency.
Heck's fire, maybe I can't hear that frequency.
Weighing Powder - How precise is good enough?
- Thread starter jdbove
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SBruce, that ain't no funny
Think about our dogs using our long rangeweapons to get us!!!! Man!!!!
Then again I may think like that because mydog is a back yard dog... lightbulb
Mikecr
Well-Known Member
If you can't get consistent readings and accuracy with a Chargemaster(within a couple kernels or better), there is a problem with it, or with it's use.
I was an early adopter and worked with mine for the first year, comparing every charge weight on an Acculab, which goes another place more accurate. This was a real pain but I stayed objective with it. As a result of this, I was able to see what was going on, tune it's operation, and easily call a bad charge -vs- a keeper.
Eventually there was no further need for the Acculab, and good riddance to it(very accurate and terrible reloading scale).
With my CM I can dispense most charges with greater accuracy than CMs spec at. With IMR7828, this is to single kernel. With something like H322, it's 2-3 kernels.
I think I've seen drifting issues you're referring to, and they are predictable and easy to manage. If you leave a charge on the scale, it will drift away from that charge over time, as the program constantly tweaks for null. It was designed to do this as part of it's self zeroing function(which works well). RCBS should further develop their program to cease nulling when the measure is outside an obvious window. You should see how much an Acculab re-nulls away.. It actually does have to be re-zero'd for every reading! But then, it is very very accurate.
Personally, I'd like to turn off ALL nulling, and read the scale like a beam.
Anyway, you can see that 'fresh' readings are accurate, and dump any charge that is suspect, whether it be an 'old' dispense, or an avalanche kernel fall, to cause overcharge.
My early revision of the CM has a program flaw that switches from zero null, to nulling the entered/desired value. This would cause it to always read a charge as perfect regardless of what it actually was. To manage this & see my actual charge weight, I disturb & re-disturb the pan after the beep/wife whine, and see the weight directly settle within 2sec to the desired value. If it don't occur within 2sec, the desired value nulling will then adjust it.
So knowing this, you get a feel for it quick. If it isn't solid on this, ho-hums around it, I dump that charge & re-dispense. In other words, I pay attention to it just as I would manually trickling.
You have hysteresis with beam scales that also bring you to disturbing the measure/re-reading to gain confidence and accuracy in your readings. Again, it has to be pay'd attention to.
There are good programming settings & DIY mods out there for the Chargemaster. They are worth it. I've provided an externally adjustable trickle speed to mine for tuning with different powders, and installed a straw in the tube.
I was an early adopter and worked with mine for the first year, comparing every charge weight on an Acculab, which goes another place more accurate. This was a real pain but I stayed objective with it. As a result of this, I was able to see what was going on, tune it's operation, and easily call a bad charge -vs- a keeper.
Eventually there was no further need for the Acculab, and good riddance to it(very accurate and terrible reloading scale).
With my CM I can dispense most charges with greater accuracy than CMs spec at. With IMR7828, this is to single kernel. With something like H322, it's 2-3 kernels.
I think I've seen drifting issues you're referring to, and they are predictable and easy to manage. If you leave a charge on the scale, it will drift away from that charge over time, as the program constantly tweaks for null. It was designed to do this as part of it's self zeroing function(which works well). RCBS should further develop their program to cease nulling when the measure is outside an obvious window. You should see how much an Acculab re-nulls away.. It actually does have to be re-zero'd for every reading! But then, it is very very accurate.
Personally, I'd like to turn off ALL nulling, and read the scale like a beam.
Anyway, you can see that 'fresh' readings are accurate, and dump any charge that is suspect, whether it be an 'old' dispense, or an avalanche kernel fall, to cause overcharge.
My early revision of the CM has a program flaw that switches from zero null, to nulling the entered/desired value. This would cause it to always read a charge as perfect regardless of what it actually was. To manage this & see my actual charge weight, I disturb & re-disturb the pan after the beep/wife whine, and see the weight directly settle within 2sec to the desired value. If it don't occur within 2sec, the desired value nulling will then adjust it.
So knowing this, you get a feel for it quick. If it isn't solid on this, ho-hums around it, I dump that charge & re-dispense. In other words, I pay attention to it just as I would manually trickling.
You have hysteresis with beam scales that also bring you to disturbing the measure/re-reading to gain confidence and accuracy in your readings. Again, it has to be pay'd attention to.
There are good programming settings & DIY mods out there for the Chargemaster. They are worth it. I've provided an externally adjustable trickle speed to mine for tuning with different powders, and installed a straw in the tube.
Some very good points in this thread.
I recently purchased the RCBS CM 1500 scale\dispenser. Mikecr has the CM discernment down perfectly.
Drifting - I have seen a +.2 or +.3 drifting a few times if I walk away and come back 30 minutes later. I have also seen it hold perfectly for longer times so this is just one thing to take into consideration.
Avalanche kernel fall - yup.. I see this happen on occasion. I modify by either dumping the load and redispensing or I remove a kernel or two and re-weigh to make the load useable.
Customized settings -some neat things can be done to one's custom liking. Just make sure you "know" what you are really doing.
The straw thing - I have to research that a bit more.
More Accurate Scales - Reviewing my reloading practices and results, I believe Boomtube has a very clear understanding if there is a need for a scale more precise.
In my reloading experience I also have found there is a "window or range of margin" within the tuned powder charge. That window is almost always + or - .1 (e.g. tuned charge = 57.2; deviation 57.1 and 57.3), but I have seen it + or - .2 (e.g. tuned charge = 57.2; deviation 57.0 and 57.4). Even of just recently with 4 different rifle loads tuned, stepping out of the tuned load +- .3 or more not only opend the group, but for a couple of rifles, opened the group significantly more than 1".
..but ... I have found one exception to this experience result. If the bullet seating is "on or into the lands", for some reason the groups barely if any changed even out at 200+ yards. Again with my experience, the powder charge can be modified by even by as much as 1.5+ grains and the groups stayed almost the same.
I understand Mikecr mentioned one expert found that even a "kernel" deviation made a difference ...but I am going to side with this discernment -->
"...small internal variations in individual case volume, differences in individual primer heat, even changes in the ambient temp on powder burn rate produces more potential velocity variation than truly tiny powder charge differences."
not to forget the personality of every single rifle
Just a thought: Stereo makers make stereo equipment that have specs that a human ear cannot hear ever; but they charge you for it "because it is there".
So use your own discernment but make sure you aren't drinking some kool-aid. There are some kool-aid makers out there that will next try to sell us "kernel" splitters.
I recently purchased the RCBS CM 1500 scale\dispenser. Mikecr has the CM discernment down perfectly.
Drifting - I have seen a +.2 or +.3 drifting a few times if I walk away and come back 30 minutes later. I have also seen it hold perfectly for longer times so this is just one thing to take into consideration.
Avalanche kernel fall - yup.. I see this happen on occasion. I modify by either dumping the load and redispensing or I remove a kernel or two and re-weigh to make the load useable.
Customized settings -some neat things can be done to one's custom liking. Just make sure you "know" what you are really doing.
The straw thing - I have to research that a bit more.
More Accurate Scales - Reviewing my reloading practices and results, I believe Boomtube has a very clear understanding if there is a need for a scale more precise.
In my reloading experience I also have found there is a "window or range of margin" within the tuned powder charge. That window is almost always + or - .1 (e.g. tuned charge = 57.2; deviation 57.1 and 57.3), but I have seen it + or - .2 (e.g. tuned charge = 57.2; deviation 57.0 and 57.4). Even of just recently with 4 different rifle loads tuned, stepping out of the tuned load +- .3 or more not only opend the group, but for a couple of rifles, opened the group significantly more than 1".
..but ... I have found one exception to this experience result. If the bullet seating is "on or into the lands", for some reason the groups barely if any changed even out at 200+ yards. Again with my experience, the powder charge can be modified by even by as much as 1.5+ grains and the groups stayed almost the same.
I understand Mikecr mentioned one expert found that even a "kernel" deviation made a difference ...but I am going to side with this discernment -->
"...small internal variations in individual case volume, differences in individual primer heat, even changes in the ambient temp on powder burn rate produces more potential velocity variation than truly tiny powder charge differences."
not to forget the personality of every single rifle
Just a thought: Stereo makers make stereo equipment that have specs that a human ear cannot hear ever; but they charge you for it "because it is there".
So use your own discernment but make sure you aren't drinking some kool-aid. There are some kool-aid makers out there that will next try to sell us "kernel" splitters.
SBruce
Well-Known Member
SBruce, that ain't no funny
weapons to get us!!!! Man!!!!
dog is a back yard dog... lightbulb
Wouldn't it suprise the heck out of ya if you walked into your bedroom and saw this? Lets just hope that beep doesn't give them an itchy trigger paw too!
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Kevin Rohrer
Well-Known Member
When working up a load, I use a B&M measure to get close, then trickle up to the exact number. When loading to shoot, my measures get to within .10gr or so. The larger the load, the less important a consistently accurate load becomes. For example, for rifle loads of 36.0 grains of something, a load of 36.1 or 36.2 isn't a consideration unless you are dealing with max loads. The difference is <.10% and inconsequential.
Mikecr
Well-Known Member
Kevin +/- 0.1gr is +/-10fps from my 6br using 31.6gr IMR4895.
Now 10fps by itself isn't much.
But while I'm trying to find the lowest ES, best shooting load, it would be difficult to accept that much error before even leaving the bench..
I might feel better about that kind of error with a larger cartridge.
Now 10fps by itself isn't much.
But while I'm trying to find the lowest ES, best shooting load, it would be difficult to accept that much error before even leaving the bench..
I might feel better about that kind of error with a larger cartridge.
I feel sorry for the dog!
There's supposedly alot of world class record groups shot with charges that were only metered, never weighed.
Yes that is possible at 100 yards, but absolutely never at 1000!
1k loads are weighed to the 1/10 if not .05 grains or less. If you do not, vertical will eat you alive every time.
Now that might work for "hitting a 3 ft rock" but that will equate to 6-10 inches of excess vertical in a group at 1k. Now many think that is close enough, and if it is for you go for it.
Here is a link on a new electronic scale that seems to be working very well. http://bulletin.accurateshooter.com/2011/08/review-of-the-gempro-250-scale-from-my-weigh/
I use a Ohaus Navigator that weighs to the .05 grains
BTW you can search 6mmbr for the guy who will "tune" the beam scales like the 10-10 for $20. Couple guys I know really like his work and say it makes a difference in there use.
BH
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Wouldn't it suprise the heck out of ya if you walked into your bedroom and saw this? Lets just hope that beep doesn't give them an itchy trigger paw too!
Yes it would!!! That's a cool picture!
Based upon Blackknight's advice above, I Googled a bit and found a page that instructs on the method for disabling the beep tone on an RCBS Chargemaster. Turns out all you have to do is hold down the 'zero' button for about 5 seconds and the screen flashes 'beep off'. Simple as that. Between that and the reassuring advice in numerous posts, looks like I am saving my money! (Good thing, too- I'm saving up for a suppressor). Dog and wife are both happy, thanks for a good thread!
Broz
Well-Known Member
Sorry for the slow reply SBruce, I just sumbles back into this thread.
I have both a Lyman 1200 ( that I feel is very accurate and I have used it for years) and a RCBS ChargMaster Combo I recently bought with a bunch of reloading stuff.
I zero Cal. my scales with each use. Plus I always have a bullet that is close to my charge weight that I set in the pan once in a while to quick check. I weigh to the tenth of a grain. That is as close as the scales will go but if it flickers back and forth between numbers I take a few kernal out or add one. I think with H-1000 2 kernals are about 1/10th of a grain and I get them all perfect to the tenth. May not be the best way but it works for me and it makes me feel knowing I left no variation. Just not that hard to be perfect in this area.
Jeff
