Which is more important to obtain consistent loads? It seems to me that ball or flake powders which measure well out of powder throwers are more consistent in weight as opposed to stick powders. However, if you measure stick powder by weight, the amount of volume in a case (e.g. necked rifle case) is less consistent. Since stick powders have different size "sticks", I can't have both consistent weight and volume. Any thoughts?
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Weight vs volume
- Thread starter DMY
- Start date
lordmorgul
New member
Calories of energy available from burning the fuel depends on the compound and mass; the burn rate depends on the volume consumed by fuel and volume available to expanding burning gasses. The right answer is both... but the density of your metered volume would have to be very consistent and we know a stick powder is not. A compressed load eliminates some of the uncertainty because the available volume for ignition is consistent.
For basic plinking loads use volume. For accuracy or consistency use mass because controlling the total calories is the bigger effect, the rate of consuming them is secondary but not unimportant (especially in short barrels like 3” handguns where it’s possible you’re not fully burning the powder under pressure, and maybe you need to change powder if that’s the case to a different burn rate).
I personally prefer powders with smaller size so that I can meter volume and double check weight consistency. I do pretty well at low 20s deviation in velocity with Accurate LT-32 for 5.56 and 308 Win and a powder thrower because it meters so smoothly.
Andrew - Lancaster, CA
NRA Life Member, Calguns.net contributor, CGF / SAF / CRPA / FPC / USCCA member
For basic plinking loads use volume. For accuracy or consistency use mass because controlling the total calories is the bigger effect, the rate of consuming them is secondary but not unimportant (especially in short barrels like 3” handguns where it’s possible you’re not fully burning the powder under pressure, and maybe you need to change powder if that’s the case to a different burn rate).
I personally prefer powders with smaller size so that I can meter volume and double check weight consistency. I do pretty well at low 20s deviation in velocity with Accurate LT-32 for 5.56 and 308 Win and a powder thrower because it meters so smoothly.
Andrew - Lancaster, CA
NRA Life Member, Calguns.net contributor, CGF / SAF / CRPA / FPC / USCCA member
Last edited:
Powder charges are based on "weight" but are often dispensed by volume as an expedient. Under no circumstances should volume be the only unit of measure for powder charges.
I've found that multiple powders I've tried for .223 loads have measured out to very similar volumes often requiring only minor tweeks of the measure.
Finding a "sweet spot" of powder filled case capacity for a given cartridge makes further loading much easier.
I've found that multiple powders I've tried for .223 loads have measured out to very similar volumes often requiring only minor tweeks of the measure.
Finding a "sweet spot" of powder filled case capacity for a given cartridge makes further loading much easier.
Powder charges are based on "weight" but are often dispensed by volume as an expedient. Under no circumstances should volume be the only unit of measure for powder charges.
I think that's a good place to start and understand .
After that I'd say it depends on the need . The only time I weigh every charge on a handgun charge is during load development . After that the scale and charge is checked with check weights and I throw the rest while weighing every tenth throw or so . That's because I'm not trying to shoot sub moa at 200yds with my M&P shield . I hit what I'm aiming at with just throwing my handgun charges why start making it harder to load those when "I" wont notice the difference .
On the other hand I weigh almost every rifle charge regardless of cartridge except my 223/5,56 plinking loads that I use H-335 with . H-335 throws so well for me I have no issues doing so . Most all my other rifle powders are stick powders and they just don't throw all that well . The two worst I've found are IMR 4064 and IMR 4350 . I can't get better then a +/- of .3gr or ES of .6gr with those two powders . That's a lot , especially in a small case like the 223 . In a 50BMG I'd likely not care one bit of a .6gr variance but in a 223 that's 60fps+ which will blow up your ES/SD .
Hammerhead
New member
Stick (rifle) by weight, ignoring volume diff's. I'm not a high volume rifle shooter.
Handgun powders I meter by volume. I have settings recorded for each charge combo. I just dial in the setting on my meter, check that it's within .1 grain and run, checking every 10th with a scale.
I do use small stick handgun powders like N340 and N310 in my meter with no problems.
Handgun powders I meter by volume. I have settings recorded for each charge combo. I just dial in the setting on my meter, check that it's within .1 grain and run, checking every 10th with a scale.
I do use small stick handgun powders like N340 and N310 in my meter with no problems.
Don Fischer
New member
You can throw stick powder accurately by the way you work the press. Take the handle up to fill and then bump the handle a couple time's. You'd be surprised how accurate you can be. But it does require the same bump every time. I have done it and find that now and again I don't do it the same and come up a bit short. So I always set the dispenser a few tenth's low and trickle up loads. If I was doing a lot of rounds at one time I'd consider using a ball powder. They measure very well. To see why bumping works, throw a charge of stick powder in a case that will pretty much fill it. Look and see where the case is filled to. Now put your thumb on the base and a finger over the mouth and tap on the side of the case several times then look in the case and the same charge will not come up quite so fat. You have settled the stick powder.
You see some reports of volumetric measured stick powder actually being more consistent than what is measured by weight. it is true that less consistent weight means you are not throwing the same amount of stored energy, but stick powder throws get their different volumes by how the sticks packed in the metering chamber of the powder measure. The more tightly they pack, the harder it is for the ignition flame to pass through the powder so the slower their burning rate gets.
Hatcher reported that one year (1920's) he tested two powders with burn rates similar to the later-developed IMR 4320. One was a short stick grain that the arsenal loading machines could meter to within a spread of 0.6 grains, while the other was a coarse stick which the equipment could only hold to a spread of 1.7 grains. Yet the latter powder's ammunition was consistently more accurate and wound up being that years NM load and several records were set with it. Apparently packing and burn rate compensated nearly ideally for charge weight differences with that powder in the .30-06 with M1 Type match bullets.
This tendency of stick powder burn rate to change with packing density makes it harder to be sure what will happen. The 1995 Precision Shooting Reloading Guide had an example from, IIRC, Dan Hackett, of a stick powder load that worked fine when the author loaded it at home, but caused sticky bolt lift when loaded at the range. He finally tracked it down to the vibration in his vehicle packing the powder down while he was driving to the range, lowering its burn rate.
Weighing has its limitations, too. The Norma manual points out powder burn rate can change as much as 12% depending on what humidity it is kept in. It can hold up, IIRC, about 1.5% water by weight, so a high humidity (>80%) charge weight will rob you of that much energy content as compared to a desiccated sample of powder.
So, what's a body to do?
Well, for one thing, you want to keep your powder in constant RH. Norma says they keep it between 40-60% RH until it is packed and shipped. 70% is another common storage number for powder. You mainly want to pick a number you can reasonably maintain and stick with it and keep any ammo you load in advance in that same humidity as Norma points out the powder in unsealed cartridges equilibrates to storage RH over about a year.
Second, use a powder that provides peak accuracy (obviously) and that fills the case well. I think this is one of the secrets of Federal's .308 Win Gold Medal Match load with the Sierra 168 grain bullet. The charge of 43.5 grains of their special lots of IMR 4064 is about 0.5% compressed. That locks the powder grains in place and prevents vibration from compacting the powder and changing burn rate. Note that this does not appear to be an issue with spherical propellants as they don't pack appreciably (the reason they meter consistently). I once pulled down some Winchester Supreme .308 Win 168 grain bullet match loads that had what looked like 748 in them. They charge weight spread on my lab scale was an astonishing 0.05 grains. But it didn't shoot as well as the Federal, which had a 0.4 grain spread in the sample I pulled down.
Third, when I'm trying to make super-precise loads with stick powder, I use both volume and weighing. I have JDS Quick Measure that is very consistent with stick powders. It guarantees no more than 0.2 grains error, and I find it comes closer to 0.1 grains in most instances. Zero you scale with the primed, empty case on it. Throw the charge and keep only the ones that match weight as exactly as the scale reads. You can also throw an intentional half a grain low and trickle up on the scale to final weight on the assumption that adding that last little bit won't affect the packing under it, but I haven't tested it to see if it can settle the powder a little or not. The advantage of the volumetric measure here is that it not only sorts out the powder density but if you leave it set for the same powder it will average at the same energy density of charge, whether the powder has changed moisture content or not.
Fourth, if you want to dispense powder by weight and you can keep your humidity consistent enough, then you want to be sure you get consistent packing density when you move the powder from the weighing pan to the cartridge case. This means picking tha pan up and using the same powder funnel, held at the same angle and pouring powder into it at the same rate every time. Just like working a powder measure, consistency of motion and method get you consistency on the target paper.
Hatcher reported that one year (1920's) he tested two powders with burn rates similar to the later-developed IMR 4320. One was a short stick grain that the arsenal loading machines could meter to within a spread of 0.6 grains, while the other was a coarse stick which the equipment could only hold to a spread of 1.7 grains. Yet the latter powder's ammunition was consistently more accurate and wound up being that years NM load and several records were set with it. Apparently packing and burn rate compensated nearly ideally for charge weight differences with that powder in the .30-06 with M1 Type match bullets.
This tendency of stick powder burn rate to change with packing density makes it harder to be sure what will happen. The 1995 Precision Shooting Reloading Guide had an example from, IIRC, Dan Hackett, of a stick powder load that worked fine when the author loaded it at home, but caused sticky bolt lift when loaded at the range. He finally tracked it down to the vibration in his vehicle packing the powder down while he was driving to the range, lowering its burn rate.
Weighing has its limitations, too. The Norma manual points out powder burn rate can change as much as 12% depending on what humidity it is kept in. It can hold up, IIRC, about 1.5% water by weight, so a high humidity (>80%) charge weight will rob you of that much energy content as compared to a desiccated sample of powder.
So, what's a body to do?
Well, for one thing, you want to keep your powder in constant RH. Norma says they keep it between 40-60% RH until it is packed and shipped. 70% is another common storage number for powder. You mainly want to pick a number you can reasonably maintain and stick with it and keep any ammo you load in advance in that same humidity as Norma points out the powder in unsealed cartridges equilibrates to storage RH over about a year.
Second, use a powder that provides peak accuracy (obviously) and that fills the case well. I think this is one of the secrets of Federal's .308 Win Gold Medal Match load with the Sierra 168 grain bullet. The charge of 43.5 grains of their special lots of IMR 4064 is about 0.5% compressed. That locks the powder grains in place and prevents vibration from compacting the powder and changing burn rate. Note that this does not appear to be an issue with spherical propellants as they don't pack appreciably (the reason they meter consistently). I once pulled down some Winchester Supreme .308 Win 168 grain bullet match loads that had what looked like 748 in them. They charge weight spread on my lab scale was an astonishing 0.05 grains. But it didn't shoot as well as the Federal, which had a 0.4 grain spread in the sample I pulled down.
Third, when I'm trying to make super-precise loads with stick powder, I use both volume and weighing. I have JDS Quick Measure that is very consistent with stick powders. It guarantees no more than 0.2 grains error, and I find it comes closer to 0.1 grains in most instances. Zero you scale with the primed, empty case on it. Throw the charge and keep only the ones that match weight as exactly as the scale reads. You can also throw an intentional half a grain low and trickle up on the scale to final weight on the assumption that adding that last little bit won't affect the packing under it, but I haven't tested it to see if it can settle the powder a little or not. The advantage of the volumetric measure here is that it not only sorts out the powder density but if you leave it set for the same powder it will average at the same energy density of charge, whether the powder has changed moisture content or not.
Fourth, if you want to dispense powder by weight and you can keep your humidity consistent enough, then you want to be sure you get consistent packing density when you move the powder from the weighing pan to the cartridge case. This means picking tha pan up and using the same powder funnel, held at the same angle and pouring powder into it at the same rate every time. Just like working a powder measure, consistency of motion and method get you consistency on the target paper.
I thought about this a bit last eve and here is what I think
If you are shooting beyond 300 then a consistent velocity matters. I can take 50 cases, prep them identically and trim all to within .001 of each other. Seat all primers perfectly and load all with powder measured to within a kernel of Varget. Take them to the range and fire them over a chrony and get all sorts of extreme spreads and standard deviations.
I have also load tested where maximum velocity may be no more than 25 FPS for four or five tenths of a grain from lowest load to highest then you go up a tenth grain more and have the velocity jump 50 FPS.
My theory is that each cartridge and bullet will have sweet spots where the case fill is perfect for the primer and powder burn rate. Once you find that sweet spot the weight/volume can be off a bit one way or the other and the ammo will perform at any distance
I will be doing a new load development later this week weather permitting and if I find one of those wide flat spots I will make a thread with pics.
If you are shooting beyond 300 then a consistent velocity matters. I can take 50 cases, prep them identically and trim all to within .001 of each other. Seat all primers perfectly and load all with powder measured to within a kernel of Varget. Take them to the range and fire them over a chrony and get all sorts of extreme spreads and standard deviations.
I have also load tested where maximum velocity may be no more than 25 FPS for four or five tenths of a grain from lowest load to highest then you go up a tenth grain more and have the velocity jump 50 FPS.
My theory is that each cartridge and bullet will have sweet spots where the case fill is perfect for the primer and powder burn rate. Once you find that sweet spot the weight/volume can be off a bit one way or the other and the ammo will perform at any distance
I will be doing a new load development later this week weather permitting and if I find one of those wide flat spots I will make a thread with pics.
Smokeless powder is weighed by weight, not volume, regardless of the shape of the granules. Black powder is weighed in grains but by volume.
Some powder charges are compressed. Means the bullet packs the powder into the case. Compressed loads are nothing to worry about. They have nothing to do with volume though.
The whole thing isn't something you need to worry about as long as you follow your manual.
Some powder charges are compressed. Means the bullet packs the powder into the case. Compressed loads are nothing to worry about. They have nothing to do with volume though.
The whole thing isn't something you need to worry about as long as you follow your manual.
T. O'Heir said:Smokeless powder is weighed by weight, not volume, regardless of the shape of the granules.
Of course, things are weighed by weight. That's what weighing is, finding the weight of something. Weight is how much force gravity applies to the thing being weighed.
Mostly, people actually measure powder by mass, not weight, even if their scales are calibrated in grains. A spring scale will measure actual weight, but a balance or an electronic scale calibrated with check weights is actually measuring mass and giving you what the weight would be in an ideal 1 g, regardless of the exact gravitational value at your location. A balance always balances when the pull of gravity applies the same torque to both sides of the knife edge and will give you the same result on the moon that it does on earth, where a spring scale will not.
Powder may be dispensed by mass, however, it is also dispensed by volume based on the idea its bulk density will remain constant enough to do that and still get reasonably close to the same weight in each charge. Virtually all commercial ammunition is charged with powder dispensed by volume. You need only visit a gun store to get a tiny idea of how much volumetrically dispensed smokeless powder is really out there. The American public consumes around 15 billion rounds of volumetrically charged commercial rounds annually.
Ok, now I am going to have to take some of my hard earned dollars and buy a 20 pack of 30-06 or 308 and see what he weight variation is.
And is there any explanation as to you rely measuring mass and not weight with a balance or electronic scale?
Something that does to require physicists, trigonometry, I ok with simple algebra .
And is there any explanation as to you rely measuring mass and not weight with a balance or electronic scale?
Something that does to require physicists, trigonometry, I ok with simple algebra .
put 5 woodworkers in 5 shops and tell them to join two pieces of wood together and they will use 5 different methods and all are correct. If it works for you do it, if it doesn't then change to something that does
reloaders love to overcomplicate. In 1973 Mac McMillan shot a .009″ five-shot group in a 100 yard benchrest match. That record stood until 2013. The amazing part is he shot it without a electronic scale or a 1500 dollar induction annealer
reloaders love to overcomplicate. In 1973 Mac McMillan shot a .009″ five-shot group in a 100 yard benchrest match. That record stood until 2013. The amazing part is he shot it without a electronic scale or a 1500 dollar induction annealer
RC20,
Yes, I believe the AMU armorers did some testing in this regard, but I can't recall their conclusions. I'll check with a couple of sources on that. The topic has come up in numerous articles and forums over time and they are easy to find.
In general, the humidity changes and influences that cause errors when weighing are smaller than the ones some measures can bring about with some measures, but not all. If you are throwing spherical powder, for example, and are keeping 50-grain charges within 0.1 grains, that's only 0.2% of charge, which is less than the error changing RH value can bring about. If, for example, your powder gains 1% over an 80% RH swing, then a 16% swing in RH will produce that 0.2% change in weight, or 32% for a plus and minus 0.1-grain swing, so weighing is only director be more accurate if your humidity swings less than that.
The reason weights are given in most manual data instead of volume is that bulk density from lot to lot can change by up to ±6% with some powders (Western publishes this for Accurate Powders), so just going by volume gives you that potentially much larger starting load error. You always want to start out developing a load for a new lot of powder by weight first, for that reason, then determine the bulk density for your lot to make volumetric changes.
The mass thing is simple. Imagine the basic two-pan balance like the statue of Justice holds up above her blindfold. You put two equal masses that weigh, say, 60 grains in each pan and they will balance and the pointer will be on the zero mark. Put the balance on the moon and the two equal masses will still balance even though they now only weight 10 grains in the moon's weaker gravity. This is because they pull the scale pans down with equal for, even though that is only 1/6th of what it was on earth. So the balance measures mass. If it is a beam balance, for the same reason, it will still balance on the moon: the mass in the pan and the masses of the counterpoise weights are the same and their weights are equally smaller, but the weight graduations will still say 60 grains on the moon even though the weight up there is actually 10 grains.
Yes, I believe the AMU armorers did some testing in this regard, but I can't recall their conclusions. I'll check with a couple of sources on that. The topic has come up in numerous articles and forums over time and they are easy to find.
In general, the humidity changes and influences that cause errors when weighing are smaller than the ones some measures can bring about with some measures, but not all. If you are throwing spherical powder, for example, and are keeping 50-grain charges within 0.1 grains, that's only 0.2% of charge, which is less than the error changing RH value can bring about. If, for example, your powder gains 1% over an 80% RH swing, then a 16% swing in RH will produce that 0.2% change in weight, or 32% for a plus and minus 0.1-grain swing, so weighing is only director be more accurate if your humidity swings less than that.
The reason weights are given in most manual data instead of volume is that bulk density from lot to lot can change by up to ±6% with some powders (Western publishes this for Accurate Powders), so just going by volume gives you that potentially much larger starting load error. You always want to start out developing a load for a new lot of powder by weight first, for that reason, then determine the bulk density for your lot to make volumetric changes.
The mass thing is simple. Imagine the basic two-pan balance like the statue of Justice holds up above her blindfold. You put two equal masses that weigh, say, 60 grains in each pan and they will balance and the pointer will be on the zero mark. Put the balance on the moon and the two equal masses will still balance even though they now only weight 10 grains in the moon's weaker gravity. This is because they pull the scale pans down with equal for, even though that is only 1/6th of what it was on earth. So the balance measures mass. If it is a beam balance, for the same reason, it will still balance on the moon: the mass in the pan and the masses of the counterpoise weights are the same and their weights are equally smaller, but the weight graduations will still say 60 grains on the moon even though the weight up there is actually 10 grains.
put 5 woodworkers in 5 shops and tell them to join two pieces of wood together and they will use 5 different methods and all are correct. If it works for you do it, if it doesn't then change to something that does
A few years back I read an article by a guy who wanted to find out what the top bench rest shooters did for accuracy.
When it was done, while there were some common aspects, no two did it the same for something like 6 or 8 different parts of it.
I came away thinking that what gets tiny groups was faith. As long as you believe you will get tiny groups you pick a series of steps and processes and stick with it, you get tiny groups.
The mass thing is simple. Imagine the basic two-pan balance like the statue of Justice holds up above her blindfold. You put two equal masses that weigh, say, 60 grains in each pan and they will balance and the pointer will be on the zero mark. Put the balance on the moon and the two equal masses will still balance even though they now only weight 10 grains in the moon's weaker gravity. This is because they pull the scale pans down with equal for, even though that is only 1/6th of what it was on earth. So the balance measures mass. If it is a beam balance, for the same reason, it will still balance on the moon: the mass in the pan and the masses of the counterpoise weights are the same and their weights are equally smaller, but the weight graduations will still say 60 grains on the moon even though the weight up there is actually 10 grains.
I get the overall, but never occurred to me on changes in gravity.
Ok, first take is do not reload on top of Mt Everest!
Let me try to explain some things that may have already been said. First, the sticks will not be inconsistently sized, every stick will be within a few hundredths inch in length and practically identical in diameter, and since this stuff is mixed in lots of a thousand or so pounds, your lot will be as consistent as it possibly can be. Any deviation between one charge and another is only because of the way they stack up in the measure.
In theory, measuring every charge to the tenth of a grain should give you greater accuracy. In reality, unless you are deviating by .2 grains or larger, it is very unlikely that you will find accuracy issues that can be attributed absolutely to your charges.
When you have squeezed every last variable out by buying better bullets, bedding and tuning, finding the best possible load, then, and only then, should you worry about whether you're getting exactly to the .1 grain measurements. You will never, ever be able to tell if you're shooting old betsy with a randomly selected load from a manual.
In theory, measuring every charge to the tenth of a grain should give you greater accuracy. In reality, unless you are deviating by .2 grains or larger, it is very unlikely that you will find accuracy issues that can be attributed absolutely to your charges.
When you have squeezed every last variable out by buying better bullets, bedding and tuning, finding the best possible load, then, and only then, should you worry about whether you're getting exactly to the .1 grain measurements. You will never, ever be able to tell if you're shooting old betsy with a randomly selected load from a manual.
RC20 said:…no two did it the same for something like 6 or 8 different parts of it.
I came away thinking that what gets tiny groups was faith.
If I'm generous, it could just mean there is more than one way to skin a cat. If I'm more analytical, I think it suggests that a number of the precision steps make improvements that are pretty much lost in the noise. It's hard to let go of a good pet theory, but I always load test loads as precisely as possible and then, once the load is established, I start eliminating extra steps to see if I can measure any performance difference. Often, some steps turn out to have made no difference, so I stop doing them and drop the theory that they will matter in that load. However, that doesn't mean they won't matter in another load, so I'm back to square one when I work up the next one. I'm guessing those BR guys would find the same thing if they better isolated their variables by dropping or changing some steps to see what happens.