RCBS Chargemaster Combo vs Lyman 1200 DPS 3

do you then trickle on a gempro or do you just keep the chargemaster dumps?

is +-.1 grains going to make a difference in 308 poi?
(probably not at 200 yards anyway?) how far will it make a diff, or will it just not make a difference?
 
Kryogen said:
do you then trickle on a gempro or do you just keep the chargemaster dumps?

is +-.1 grains going to make a difference in 308 poi?
(probably not at 200 yards anyway?) how far will it make a diff, or will it just not make a difference?
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Forgive me for rambling, but I've thought a lot about this.

Right now I definitely trickle using the GemPro until the load is as accurate as I can make it. Given that that scale can detect (close to) single grain differences of extruded powders like IMR 3031 or H322, that means I'm trickling a few grains at a time or picking grains out of the pan one or two at a time with tweezers.

I'm only doing this because:

a) I can be a bit obsessive
b) I'm fairly new to reloading
c) I'm working on a ladder test so I want all the loads to be as consistent as possible

but, maybe mostly: d) that level of accuracy is available to me and I get itchy if I see that the scale is off at all

I really can't say how much of a difference +/- .1 gn will make in .308. I would suggest that it's not an insignificant level of inaccuracy when you are taking about a .223 load that has around 20 grains of powder, but there are simply too many factors in play to say that definitively. Does the powder charge scale linearly in terms of pressure and muzzle velocity? I dunno.

Clearly, when you start loading bigger calibers with many more grains of powder, the margin of error diminishes greatly in proportion to the size of the overall load.

I'm still working this stuff out, personally, but my sense is that up to a 5% variance in consistency of charges between cartridges, when pushing the effective range of your cartridge, when you're shooting for the best accuracy possible, is enough to take measures to make sure that your loads are as consistent as possible.

But.. Shooting at 200 yards? Maybe not really worth worrying about.

And.. how accurate is accurate? The GemPro can measure down to 1/50th of a grain. E.g.: the difference between 20.1 and 20.12. For the extruded powders I mention above, that's literally a flake (or just a little more than a flake). So maybe being within .04 gn or .06 gn is fine.

For instance, here's Hornady's load data for their 55gr FMJ-BT using IMR 3031:

20.5 gr (min recommended charge) = 2800 fps
21.2 gr = 2900 fps
22.0 gr = 3000 fps
22.8 gr (max recommended charge)= 3100 fps

That means that there's .7 - .8 gn difference of IMR 3031 required to move the bullet 100 FPS faster (for context purposes, 100 FPS is about 1/3 the speed of a typical paintball :)). In that context, being .1 gn out probably isn't going to a worthwhile difference, particularly at shorter ranges.

It also means that, if I were loading the min load or the max load, I would be far more anal about double-checking the charge thrown by the Chargemaster.

And.. what does RCBS actually mean when they state +/- .1 gn of accuracy? Does that mean a charge reading 20.1 gn on the scale might actually be 20 or 20.2? Maybe.. but in my (limited) experience with the Chargemaster so far it's far more accurate than that. I think what's going on is that the scale is sensitive enough that it tends to round to the nearest tenth of a grain. So if it gets up to 20.04 it'll call that 20. And if it gets to 20.06 it'll call that 20.1. That means that you have an effective difference of a tenth of a grain overall, not 'up to .1 grain above your desired charge or .1 grain below your desired charge', which would work out to up .2 gn overall variation.

So, no definitive answer, at least for me. In short, the degree to which I feel I need to be anal varies with:

* How far I'm shooting -because inaccuracies are multiplied over distance
* How heavy the desired charge is - because the inaccuracy of the scale does not vary with the size of the charge so, the heavier the desired charge, the less the margin of error is going to matter
* What I'm shooting for - if it's a competition with my bolt action or if I'm trying to find ideal loads (like now) then I'm going to be super anal. If I'm loading for a semi-auto for some weekend fun, I won't care nearly as much
* How close I am to the recommended min/max charge weights

I'd be very interested in what more experienced reloaders think.
 
The answer to this question is easy. Don't get either of them!
The 1 digit weighing accuracy of either of them is barely able to hold .4 grains on a real good day and under ideal conditions.

My advice is to spend the same amount of dollars on a more accurate 2 or 3 decimal place scale.

On the other hand if you are just loading short range rattle battle blaster ammo just use a powder thrower.

I sold off my chargemaster. I now use both the powder thrower and a 3 decimal place scale. I throw the charge close and then fix it up on the good scale.

Sometimes if I'm not loading many rounds, I don't even use the thrower, just the Lyman powder spoon and then fix up the load on the scale.

Bottom line is that a 3 decimal place scale will give you accuracy within less than a single kernel of Varget. You might even be tempted to cut kernels in half, but then you just take your OCD pills and that goes away.
 
BadAsMo said:
The 1 digit weighing accuracy of either of them is barely able to hold .4 grains on a real good day and under ideal conditions.
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You'll have to explain that one-- the scales are claimed to be accurate to within .1 gn, and a ton of tests by a bunch of different people show that they are at least that accurate. Do you maybe mean .04 gr?

BadAsMo said:
Bottom line is that a 3 decimal place scale will give you accuracy within less than a single kernel of Varget.
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As I understand it, a kernel of Varget weighs about .03 gn. So (as an example) the GemPro 250 is able to resolve less than a single kernel. Assuming you can't subdivide kernels, and that they're all of a uniform size and weight, what's the point of the extra digit of precision?

Which scale are you using, BTW? Maybe I wanna go buy one :)
 
You guys are far, far too anal about your weighing of powder!! Three decimal places?? Get a Grip!! :rolleyes:
The .1 grain difference will make absolutely no perceptible difference in a 45 grain charge of powder [On the target, that is]

Many of the best BR shooters use a powder measure, not a scale to dump their charges.
They use a scale to set the measure, and then go for it....they win matches that way, too.

I compete at 1000 yards each spring.
I weigh each powder charge for that game, and I would like to see it exact. [not worried about 3 decimal places, though, lol]

But for hunting, and casual shooting out to 400 yards or a bit more, I do not worry about the .1 grain spreads.

Never missed an animal yet that could be attributed to the powder charge difference.

Often shoot groups at 400 yards that are under moa [4" at 400 yards] so the difference is inconsequential.

Other factors play a much larger part in accuracy. [neck tension, bullet runout, etc, etc]

A hobby like this is supposed to be fun, not fretting about that .001 grains of powder, lol

So get up to that bench and enjoy yourselves. Take a double dose of anti-OCD pills. :D

FWIW, I only started reloading in 1964, so take what I say with a grain of salt :)

Cheers, Dave.
 
ok according to a quick Isnipe calculation using a hornady match bullet with a theorical spoeec of 2600 fps
cutting .1 gn off a load of 44gn would reduce speed by +- 4.3 fps, which would shift the poi .3 in at 500 yards, and 1.7 in at 1000
.02 gn would do .2 at 500 and 1.3 in at 1000

Now, that's not anything real life, just wanted to calculate it to see.
That means the OCD (.1 grains is just .1 inch at 400 yards), no diff under that.
So for 300 yards or less, you will not see a difference on a 308 load with a .1 difference. So the chargemaster is plenty accurate I would say.
More than 300 yards, I would try just to see. Of course all the other case variables are going to alter the results also... wind drift, etc.

Oh well, just had time to loose this morning, have a good day.
 
You guys are far, far too anal about your weighing of powder!! Three decimal places?? Get a Grip!!
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Hehe, I've already copped to being a bit anal, but even I think it's going too far to measure a level of accuracy that you can't actually reach because it's more precise than a single kernel of powder. :)

I compete at 1000 yards each spring.
I weigh each powder charge for that game, and I would like to see it exact. [not worried about 3 decimal places, though, lol]
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I'm super curious about this because this is exactly the application I'm working my way up to and why I'm being so anal right now..

What calibre do you shoot at 1000 yards? When you say you'd like to see it exact, practically speaking, how exact do you go?

When I start loading .308 I'll probably worry less about the difference of .1 gn. For .223, it's more significant.

All I do is punch paper, so I'm only interested in how far apart the holes are in each group..

FWIW, I only started reloading in 1964, so take what I say with a grain of salt
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Best subtle smack-down ever. ;)
 
Kryogen said:
ok according to a quick Isnipe calculation using a hornady match bullet with a theorical spoeec of 2600 fps
cutting .1 gn off a load of 44gn would reduce speed by +- 4.3 fps, which would shift the poi .3 in at 500 yards, and 1.7 in at 1000
.02 gn would do .2 at 500 and 1.3 in at 1000

Now, that's not anything real life, just wanted to calculate it to see.
That means the OCD (.1 grains is just .1 inch at 400 yards), no diff under that.
So for 300 yards or less, you will not see a difference on a 308 load with a .1 difference. So the chargemaster is plenty accurate I would say.
More than 300 yards, I would try just to see. Of course all the other case variables are going to alter the results also... wind drift, etc.

Oh well, just had time to loose this morning, have a good day.
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Hmm. Good info.

.1 gn difference in .308 is less significant because it's a smaller proportion of the overall charge size.

Running the same calculation for a .224 Hornady FMJ-BT, which is one of the bullets I'm currently working up a load for, makes a 50 FPS difference. That's a POI change of 1.5" at 400 yards. 1.5" is about a 3rd of 1 MOA at that range, so that's much more significant..
 
On this topic, I actually am having a real, honest to goodness problem with my Chargemaster that I might need to get support on.

Last night I was using Win 748 (I think I now hate ball powders and am eager to get back to using extruded stuff, which I now hate less ;) )for the first time and was struggling to get the Chargemaster to dispense anything close to what I was asking it for.

After much dickery, I finally discovered that the Chargemaster scale seemed to be measuring everything by .1 gn too heavy. The same empty powder pan weighed 143.72 gn on my GemPro 250, and 143.8 gn on the Chargemaster. I also confirmed this difference with the various checkweights I have sitting around.

This in turn lead the Chargemaster to dispense charges that were .1 gn too light.

In fact, with the ball powder, the charges were amazingly consistent and I'm kind of impressed by that. They were all almost exactly .8 gn short of what I expected them to be, every single time.

Has anyone else experienced anything like this with theirs?
 
Ball powders do tend to meter very accurately, charge to charge.

I have a very accurate balance beam scale, [RCBS 304] and check an occasional charge on it to verify.
The charges have always been virtually perfect. My other, stand-alone electronic scale also agrees.

I shoot 6mm BR and 260AI at 1000 in unlimited and heavy barrel class, 6.5x55AI in Sporter and hunter class.

For the 1000 yard loads, I want them to be equal. [not vary by .1 grain]. I also check and sort case volumes to match them up.
Necks are lightly turned for consistency and even bullet "pull." Bullets are all weighed and any that are off the nominal weight are used for fouling/practice.

I use Varget in the 6BR, VV N560 in the 6.5x55 AI, H4831SC in the 260AI.
Obviously, at 30 grains or so, the 6mm BR would be the most sensitive to charge differences.

Regards, Dave.
 
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Eagleye said:
Ball powders do tend to meter very accurately, charge to charge.

I have a very accurate balance beam scale, [RCBS 304] and check an occasional charge on it to verify.The charges have always been virtually perfect. My other, stand-alone electronic scale also agrees.

I shoot 6mm BR and 260AI at 1000 in unlimited and heavy barrel class, 6.5x55AI in Sporter and hunter class.

For the 1000 yard loads, I want them to be equal. [not vary by .1 grain]. I also check and sort case volumes to match them up.
Necks are lightly turned for consistency and even bullet "pull." Bullets are all weighed and any that are off the nominal weight are used for fouling/practice.

I use Varget in the 6BR, VV N560 in the 6.5x55 AI, H4831SC in the 260AI.
Obviously, at 30 grains or so, the 6mm BR would be the most sensitive to charge differences.

Regards, Dave.

Regards, Dave.
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:) Glad to see I'm not the only one. With my limited equipment upgrade a few years ago, I kept my balance beam scale for the same purpose. I also hung onto my old Lyman # 55 powder measure. I find it a lot quicker for loading batches of handgun ammo.
 
QUOTE=Johnn Peterson;9664120]:) Glad to see I'm not the only one. With my limited equipment upgrade a few years ago, I kept my balance beam scale for the same purpose. I also hung onto my old Lyman # 55 powder measure. I find it a lot quicker for loading batches of handgun ammo.[/QUOTE]

:) Not the only one by a long shot. I've been every bit as accurate as need be with a $100 BB scale and when accuracy matters less, my $60 powder measure tosses within +- 0.1gr with the occasional BB spot check. Lord knows I've got every gadget going but I've just never been able to get my head around the Chargemaster et al. Maybe I should pull a Pelosi and buy one, then figure out why ;).
 
make sure the scale is on 24h before you use it.
(That is what I do, and it works for me. Stop complaining, it's not like the manufacturer asked you to do that. If I want to reload one given week, I just keep it on the whole week, not like it's hard.)
no air drifts, no air temp changes.
make sure its level.

then calibrate it before use.

When I do all that, I get good readings. when I dont, I dont...
 
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Kryogen said:
make sure the scale is on 24h before you use it.
no air drifts, no air temp changes.
make sure its level.

then calibrate it before use.

When I do all that, I get good readings. when I dont, I dont...
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I think I'm going to have to call RCBS about a bum unit. Maybe. I'm not finished troubleshooting yet. I've:

* Calibrated it (many times)
* Made sure it's level
* Disabled nearby EM sources, such as lights and my WiFi router, etc.
* Tested it against multiple other scales
* Let it warm up for a several hours
* Added a decent power conditioner
* Made sure the wind shield was closed
* Ensured there were no vibrations (heavy table sitting on foam flooring, and I put a glass of water next to it to make sure there were no vibrations I couldn't see)
* Removed and reseated the platen
* Made sure there were no air currents

Etc. It still measures consistently .1 gn high vs. other scales and, on the powder pan that was included in the kit, varies every few seconds (sometimes more, sometimes less) between 143.7 gn and 143.8 gn.

Last things I'm going to try is rubbing it down with a dryer sheet and moving it to another room.

If anyone else has any suggestions I'm eager to hear them.

The incredibly frustrating thing is that it was working fine the day before yesterday.
 
I have never left my Chargemaster on for 24 hours at a time.
Usually let it warm for 10-15 mins, and fly at it!

Nary an issue, either.

Cheers, dave.
 
Eagleye said:
I have never left my Chargemaster on for 24 hours at a time.
Usually let it warm for 10-15 mins, and fly at it!

Nary an issue, either.

Cheers, dave.
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I didnt say that it was required by the manuf. I said that I try to turn it on the day before so it's fully warmed up. It works better for me with less drift.

As for switching between weights for your pan:

I weighted mine on a gempro and it was .14. Of course, since the chargemaster is accurate to .1, it always switches between .1 and .2

What I did is file a SMALL amount on the pan to get it to .10

That way the chargemaster always reads it at .1, and my weights jump less.

Now, your issue is with .1 high. This is within the tolerance of the chargemaster. There is nothing you can do about it, that scale is precise to +- .1 you will not get better results.

1- deal with it
2- trickle on a gempro

Maybe check your calibration weight on another scale, maybe its .1 high also? or your other scale is wrong.

The only way to know would be to check your checkweight with a lab analytical scale.

AND, if you confirm on a lab analytical scale, that your chargemaster is absolutely .100 over, all the time, then just ask it to dump .1 less. But I don't think that this is your issue.
 
Kryogen said:
I didnt say that it was required by the manuf. I said that I try to turn it on the day before so it's fully warmed up. It works better for me with less drift.

As for switching between weights for your pan:

I weighted mine on a gempro and it was .14. Of course, since the chargemaster is accurate to .1, it always switches between .1 and .2

What I did is file a SMALL amount on the pan to get it to .10

That way the chargemaster always reads it at .1, and my weights jump less.
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Sorry, can you be a bit more clear here? Are you saying that the value in the readout jumped around while the pan was sitting on it?

What my scale does is flip continually between one value and another while the weight it sitting on it, varying by .1 gn. It never settles on a weight. The time it takes to jump between one value and another varies -- sometimes it's 10-15 seconds, sometimes it's much shorter.

Did yours do that?

Also, this behaviour is new-- it definitely wasn't doing this the first time I used it a few days ago.
 
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