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Weighing each powder charge vs trusting a dispenser
- Thread starter Stats Shooter
- Start date
Stats Shooter
New member
read this before dropping several hundred on a new throw
Good read....not shocking either. Since they are counting on gravity, and the powder to cooperate by stacking properly, there isn't much to be gained by tightening the tolerances. I guess my RCBS uniflow is fine, or at least I can't spend my way into a better powder thrower.
Very early in my reloading "career", I couldn't afford a powder measure, so I used the powder measure from my Lee Load-All. It worked great - charge after charge always right on the money - until abrasion from the powder wore the charge bar so badly that powder was leaking through.
But, by that time, I could afford an RCBS Uniflow. The Uniflow generally works well except that some powders that don't flow well and don't uniformly settle into the metering chamber just will not meter consistently. Hi-Skor 800X is notoriously bad so I just set the meter to get the charge "close", throw the charge into the scale's pan and then trickle it up to weight. Since I load small batches and use a single stage, this works for me.
But, by that time, I could afford an RCBS Uniflow. The Uniflow generally works well except that some powders that don't flow well and don't uniformly settle into the metering chamber just will not meter consistently. Hi-Skor 800X is notoriously bad so I just set the meter to get the charge "close", throw the charge into the scale's pan and then trickle it up to weight. Since I load small batches and use a single stage, this works for me.
A factor you are leaving out is the charge itself. Even with a single powder, a slight variation in weight may have more or less impact on accuracy depending on the charge weight.
To put it simply, there are sweet spots for a given rifle/powder/bullet combination where a slight variation in powder charge won't have much of an impact on accuracy.
Which is why I do this for load development: http://www.6mmbr.com/laddertest.html
To put it simply, there are sweet spots for a given rifle/powder/bullet combination where a slight variation in powder charge won't have much of an impact on accuracy.
Which is why I do this for load development: http://www.6mmbr.com/laddertest.html
Dean Grenell said-that for handsguns, anyway-he checked his dispenser by throwing 10 charges, if they weighed exactly 10 times the desired charge he would rely on it
All of the ball and flake powders seem to throw decently, even a $20 Lee measure will throw a consistent charge with them. It's the extruded stuff that gives them a fit, and unfortunately that is the majority of the powders my rifle likes. The one exception would my .223 and TAC, it's spherical and flows like water from even a el cheapo plastic Lee
I've done the same thing but in 357 Magnum. My results were the same too, thrown charges were more consistent than weighed charges. I used Blue Dot which is a very coarse powder. I doubt you will get different results with an extruded powder in a larger case capacity high powered rifle load where differences in charge-to-charge is an even lower percentage of the total charge weight. Weighing charges is a waste of time and those electronic dispensers are a huge waste of money. Just set up a Uniflow to drop the correct weight and throw all charges into your cases. Now the micrometer adjuster for the Uniflow is a great addition. A real "what in the world was I doing without this before" moment when you get one.
Stats Shooter
New member
I just repeated the test from my initial post using 75 Grain Hornady BTHP's in my Varmint AR. BR-4 primers, lake city 15 brass..24.3 gr Varget, avg velocity 2762fps.
I weighed 50, and threw 50. I shot 10x5 shot groups each. I single loaded a couple groups, mag fed most of them. I fired some groups warm barrel, some cold barrel. But whatever I did, I did to both the thrown, and weighed charges equally.......oh and my thrower is just an RCBS uniflow with micrometer screw and baffle.
I didn't weigh each thrown charge, so I can't say for sure what the biggest spread was weightwise, but the biggest I checked was +.2 gr.
The groups were again not different enough at 200 yards to say one set was certainly better than another. Difference on average, was .19". But it was mostly horizontal, and there was a breeze. And there was basically no difference in the average vertical spread.
I must also say the accuracy node from my ladder for this load is 24.2-24.5. I load at 24.3, so there being no vertical is not surprising.
The extreme spread on the weighed charges was 21fps and 27fps on the thrown charges. Weighed charges averaged 4fps faster.
I suppose I'm not proving anything new. I'm totally doing this for myself. But the definitive test would be thrown vs weighed charges, at 600yards or more, and weighing each charge on my 5-0-5 beam scale rather than a digital gempro. Since I know the 5-0-5 is perfectly consistent.
I weighed 50, and threw 50. I shot 10x5 shot groups each. I single loaded a couple groups, mag fed most of them. I fired some groups warm barrel, some cold barrel. But whatever I did, I did to both the thrown, and weighed charges equally.......oh and my thrower is just an RCBS uniflow with micrometer screw and baffle.
I didn't weigh each thrown charge, so I can't say for sure what the biggest spread was weightwise, but the biggest I checked was +.2 gr.
The groups were again not different enough at 200 yards to say one set was certainly better than another. Difference on average, was .19". But it was mostly horizontal, and there was a breeze. And there was basically no difference in the average vertical spread.
I must also say the accuracy node from my ladder for this load is 24.2-24.5. I load at 24.3, so there being no vertical is not surprising.
The extreme spread on the weighed charges was 21fps and 27fps on the thrown charges. Weighed charges averaged 4fps faster.
I suppose I'm not proving anything new. I'm totally doing this for myself. But the definitive test would be thrown vs weighed charges, at 600yards or more, and weighing each charge on my 5-0-5 beam scale rather than a digital gempro. Since I know the 5-0-5 is perfectly consistent.
Yep, I don't think there is much difference between charges thrown to the tenth vs to the kernel at 200 yards. Even less if your in the middle of the "sweet spot".
FWIW if you have the ability to detect beam movement the 505 can be quite repeatable.
More sensitive than scales with decent reputations by a good margin.
https://www.youtube.com/watch?v=JmxBSOOL7Ks
FWIW if you have the ability to detect beam movement the 505 can be quite repeatable.
More sensitive than scales with decent reputations by a good margin.
https://www.youtube.com/watch?v=JmxBSOOL7Ks
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I have used a RCBS powder measure , with two drums for smaller or larger loads, since about 74.
I weight five or six loads for pistol and ball powder in rifle rounds.
For stick powders like H4831, I check weight for five or six loads and lock her down.
I still weight each load, for the big magnums, into the scale pan, when near maximum loads are used.
Last few grains are by trickle measure into the pan. Lot of trouble but I rarely shoot the big guns much and a hundred rounds last a while.
I weight five or six loads for pistol and ball powder in rifle rounds.
For stick powders like H4831, I check weight for five or six loads and lock her down.
I still weight each load, for the big magnums, into the scale pan, when near maximum loads are used.
Last few grains are by trickle measure into the pan. Lot of trouble but I rarely shoot the big guns much and a hundred rounds last a while.
Stats Shooter
New member
Jmorris: I saw your charge master video a while back. My digital scale is a gempro 500...0.05 gr. But it is difficult to use being as sensitive as it is. And with a 5-0-5 you don't need a perfectly level surface as you can adjust it.
Anyway, I'm still going to weigh my .300 WM F-class loads because H1000 meters terribly. And at 1k yards, .3-.5 gr matters, because .5 gr is about 30 fps in my load. Even still being in the sweet spot, my quick target program says that's enough to put me out of the x ring if I'm at 1/3 moa
Anyway, I'm still going to weigh my .300 WM F-class loads because H1000 meters terribly. And at 1k yards, .3-.5 gr matters, because .5 gr is about 30 fps in my load. Even still being in the sweet spot, my quick target program says that's enough to put me out of the x ring if I'm at 1/3 moa
I must also say the accuracy node from my ladder for this load is 24.2-24.5. I load at 24.3, so there being no vertical is not surprising.
What would be interesting to me is repeating the test outside of the accuracy node. Pick a section from your ladder where there is some vertical change between steps, and using that charge, do it again thrown vs weighed. I don't know that you would need to do another 100 rounds though (maybe 40, 20 per sample), but I think you might see different results.
And at 1k yards, .3-.5 gr matters, because .5 gr is about 30 fps in my load.
Absolutely, 1000 yards is a lot different than 200 yards and a half a grain is a lot bigger difference than a tenth.
You are thinking right though. Have the ability to make them right on the money, then test them side by side with the most expedient method you have and see if the difference is worth the extra time and energy. Only then will you know if your wasting time or not.
Stats Shooter
New member
What was your standard deviation for the charge that was weighed vs the unweighed charge?
I don't bother calculating standard deviation for velocity tests. The standard deviation, by definition, implies that 68% of rounds are within 1 SD. But another 27% are within two standard deviations and then another 4.5% are with 3 standard deviations.
If you are making match loads, or even hunting loads, and your standard deviation is 12, then almost 1/3 of your rounds could be 48 fps or more apart.
This rule assume a normal distribution, Which may or may not be true. There could be a bias towards the velocities being lower like a gamma distribution, or there could be an exponential distribution should most errors that occur,be wayyy off like a short stroke on the despinser or something.
Extreme spread however acknowledges the fact that just one round being off can ruin a hunt or a match. Extreme spread doesn't ignore that one or those three fliers, Which standard deviation does.
In the 1920's, Hatcher reported that one year he tested two stick powders with about the burn rate of IMR 4320, one with short grains and the other with long grains. He said the arsenal loading equipment could throw the short grain charges to a span of 0.6 grains (±0.3 grains), but could only hold the long stick power to a span of 1.7 grains (±0.85 grains). Nonetheless, that coarsely thrown powder produced consistently better accuracy and was used for that year's NM ammunition and several records were broken with it.
The late Dan Hackett reported a load that worked great when he put it together at home, but when he loaded it at the range he got sticky bolt lift. Same load. He finally worked out that the vibration of transporting the load to the range from his home packed the powder down enough to reduce its burn rate enough to be a good load.
The Norma manual shows that the same powder lot at the same charge weight in the same load can produce 12% difference in peak pressure depending whether it was stored in 80% R.H. or at near 0% RH. Same charge weight, 12% difference in pressure. So, why do we trust weighing to necessarily produce consistent results?
Well, here's the deal. You could, as Lee does, use bulk volume to set charges or use weight. Truly spherical propellants, like H380, don't have a wide range of possible packing geometries, like stick powder does. With that powder, either volumetric or weight dispensing produces about the same result. Weight is preferred in that instance because bulk density varies more from lot-to-lot than energy content per unit weight changes. Indeed, Western shows some of their powders having ±5.6% bulk density tolerance. That covers the whole starting to maximum charge range if you are metering by volume. So if we store our powder in the 40%-70% RH range and use weight, we're going to get a closer starting load pressure than a volumetric estimate of the starting load will. So we rely on weight to calibrate our volumetric dispensers initially.
But once you have a volumetric dispenser at the right start range and work up the load by adjusting the volume, you are doing as well as you would with weighed adjustments. The weight and volume will track very well with spherical powder because of the packing performance. A stick powder will vary more because the powder settles in the hopper and settles in the case and can have random variation due to how some stick pack. However, if the choice of the powder is best for your load, then it will be one where the change in burn rate due to change in packing density is self-compensating. If it packs a little more densely in one case, because it burns more slowly, the fact the charge is heavier is compensated for and you get lower ES.
That's one of the secrets of Federal GM .308M ammunition. The 4064 used is very slightly compressed. So even though the charge weights I've measured vary by 0.4 grains from one case to the next, the fact it is slightly compressed means the powder is locked in position as-dispensed and doesn't settle in transport to alter the burn rate.
So, what's the ultimate test? Try this: zero your primed case on your scale. Dispense the charge by volume. Re-weigh and sort your cases by that new weight until you get 50 that are all the same weight and volume, both. Return the others to the powder hopper or, if you have enough, shoot a second batch. I've not done a 50 round test like this, but I have been using this dispensing technique for test load for some time because of the theoretical consistency improvement. I also moved to the JDS Quick Measure dispenser for this as it dispenses stick powder more consistently than any other volumetric measure I have, and that means I can get all the same-weight loads I need put together more quickly than using another measure. I don't trickle up to weight because that has potential to produce a different density.
If you are going to weigh, I think the electronic dispensers are best because they loosen the powder packing up so that it tends to match bulk density on each weighing pan filled. You can get the same effect by trickling all the powder onto a standard scale. It then falls on the shooter to empty the pans into the cases in a mechanically identical fashion so as to avoid introducing variable packing. But it should be simply a matter of repeating your dispensing motions precisely. While that is theoretically correct, I have not personally compared the result to my method with the scale and JDS measure.
The late Dan Hackett reported a load that worked great when he put it together at home, but when he loaded it at the range he got sticky bolt lift. Same load. He finally worked out that the vibration of transporting the load to the range from his home packed the powder down enough to reduce its burn rate enough to be a good load.
The Norma manual shows that the same powder lot at the same charge weight in the same load can produce 12% difference in peak pressure depending whether it was stored in 80% R.H. or at near 0% RH. Same charge weight, 12% difference in pressure. So, why do we trust weighing to necessarily produce consistent results?
Well, here's the deal. You could, as Lee does, use bulk volume to set charges or use weight. Truly spherical propellants, like H380, don't have a wide range of possible packing geometries, like stick powder does. With that powder, either volumetric or weight dispensing produces about the same result. Weight is preferred in that instance because bulk density varies more from lot-to-lot than energy content per unit weight changes. Indeed, Western shows some of their powders having ±5.6% bulk density tolerance. That covers the whole starting to maximum charge range if you are metering by volume. So if we store our powder in the 40%-70% RH range and use weight, we're going to get a closer starting load pressure than a volumetric estimate of the starting load will. So we rely on weight to calibrate our volumetric dispensers initially.
But once you have a volumetric dispenser at the right start range and work up the load by adjusting the volume, you are doing as well as you would with weighed adjustments. The weight and volume will track very well with spherical powder because of the packing performance. A stick powder will vary more because the powder settles in the hopper and settles in the case and can have random variation due to how some stick pack. However, if the choice of the powder is best for your load, then it will be one where the change in burn rate due to change in packing density is self-compensating. If it packs a little more densely in one case, because it burns more slowly, the fact the charge is heavier is compensated for and you get lower ES.
That's one of the secrets of Federal GM .308M ammunition. The 4064 used is very slightly compressed. So even though the charge weights I've measured vary by 0.4 grains from one case to the next, the fact it is slightly compressed means the powder is locked in position as-dispensed and doesn't settle in transport to alter the burn rate.
So, what's the ultimate test? Try this: zero your primed case on your scale. Dispense the charge by volume. Re-weigh and sort your cases by that new weight until you get 50 that are all the same weight and volume, both. Return the others to the powder hopper or, if you have enough, shoot a second batch. I've not done a 50 round test like this, but I have been using this dispensing technique for test load for some time because of the theoretical consistency improvement. I also moved to the JDS Quick Measure dispenser for this as it dispenses stick powder more consistently than any other volumetric measure I have, and that means I can get all the same-weight loads I need put together more quickly than using another measure. I don't trickle up to weight because that has potential to produce a different density.
If you are going to weigh, I think the electronic dispensers are best because they loosen the powder packing up so that it tends to match bulk density on each weighing pan filled. You can get the same effect by trickling all the powder onto a standard scale. It then falls on the shooter to empty the pans into the cases in a mechanically identical fashion so as to avoid introducing variable packing. But it should be simply a matter of repeating your dispensing motions precisely. While that is theoretically correct, I have not personally compared the result to my method with the scale and JDS measure.
Four points of consideration. Rifle or pistol, long distance or short distance.
Simple observation from a simple mind.
All I reload is pistol and all is shot at a relative short distance from an unsupported standing position such as one would face in real life.
I just started reloading again about 1 year ago and as before was meticulous with case prep, seating primers, charging cases and seating bullets.
This time I started with a used progressive press instead of a single stage and a powder dispenser instead of dippers and a trickler..
The 1st loads I worked up I did 5 test loads in 0.1gr increments. All fired and hit the short range target with good accuracy. The only thing I could visually see or physically feel was the 1st starting load. It was weak and wouldn't lock the slide back on the final case. Otherwise I couldn't differentiate one from the other but I finally settled on one in the middle as feeling the best.
Since then I worked up a number of other loads based on that 1st one with making slight changes to seating depth and crimp and weighing each charge on my beam scale as again I am new and didn't trust myself or the powder measure and I wanted to eliminate as many variables as possible. Throughout all this I determined that the short distances for pistol, 50' or less, I could not tell the difference between 2 bullets that were charged a difference of 0.3gr or when the charge was the same and the seating depth was changed by .025". Feel was the same and so was POI and relative group size.
Now again, being a simple mind with simple needs I am no longer going to weigh every charge or measure every bullet. I have now done enough testing on my cheapo Lee Auto Disk to know that with the powders I an using I can hold well within + - 0.1gr with it more like + - 0.05gr. which is much more accurate than I can shoot!!! Now I may not be the greatest shot but at 50' I can consistently put 5 shots in an 8" circle with my 9mm and I'm 63 and wear bifocal glasses.
Simple observation from a simple mind.
All I reload is pistol and all is shot at a relative short distance from an unsupported standing position such as one would face in real life.
I just started reloading again about 1 year ago and as before was meticulous with case prep, seating primers, charging cases and seating bullets.
This time I started with a used progressive press instead of a single stage and a powder dispenser instead of dippers and a trickler..
The 1st loads I worked up I did 5 test loads in 0.1gr increments. All fired and hit the short range target with good accuracy. The only thing I could visually see or physically feel was the 1st starting load. It was weak and wouldn't lock the slide back on the final case. Otherwise I couldn't differentiate one from the other but I finally settled on one in the middle as feeling the best.
Since then I worked up a number of other loads based on that 1st one with making slight changes to seating depth and crimp and weighing each charge on my beam scale as again I am new and didn't trust myself or the powder measure and I wanted to eliminate as many variables as possible. Throughout all this I determined that the short distances for pistol, 50' or less, I could not tell the difference between 2 bullets that were charged a difference of 0.3gr or when the charge was the same and the seating depth was changed by .025". Feel was the same and so was POI and relative group size.
Now again, being a simple mind with simple needs I am no longer going to weigh every charge or measure every bullet. I have now done enough testing on my cheapo Lee Auto Disk to know that with the powders I an using I can hold well within + - 0.1gr with it more like + - 0.05gr. which is much more accurate than I can shoot!!! Now I may not be the greatest shot but at 50' I can consistently put 5 shots in an 8" circle with my 9mm and I'm 63 and wear bifocal glasses.