Powder Swelling????

[mr surveyor]

I've been working out of the same can of Unique for about a year, and for the "safety check" verified the dipper volume (yes, I use the Lee dippers, a funnel and loading block) on the scale multiple times for several months. Guess I got lazy, and felt there really wasn't a "need" to continue to verify the voume/weight relation as I had done it several times on this particular can of powder. Well, having had some rather dismal results loading some test rounds for my recently acquired SRH, tonight I decided to throw a 1.0cc scoop or two on the scale to check. It should be in the neighborhood of 9.3 gr.... measured, measured again, and was actually getting 7.8-7.9. Then dropped two 1.0 cc dippers on the scale and got 15.8 gr. Well after cussing the flimsy, hard to read Lee Safety scale for a few minutes, I decided to test a bit "finer grained" powder, and dropped a 1.0 cc scoop of AA#7 on the scale.... 15.3 gr - exactly what Lee says it should be. Checked it twice more, and 15.3 on the nose. So, having another unopened can of Unique, I thought I'd give it a try. Gave it the same multiple checks as before, and it hit the scale at 8.6 gr per 1.0cc. Not quite the 9.3 that Lee says, but much closer that the near empty can of Unique. When I first started using this particular can of Unique, I checked the .7 cc dipper multiple times and got 6.2 gr weight, which is about .2 below what Lee calls (6.4 gr). It has worked well enough with my 158 gr .357 plinkers, but I have noticed they have been a bit on the more than puny side the last few outings. Obviously I'm loading below 6 gr with this powder now.

So.... did this powder swell from too many "open-close, open-close" (it's only used in my airconditioned office in fairly low humidity)?? I can't imagine it being mechanical as the larger/lighter particulates would ordinarily gravitate to the top. But, could the last inch or so in the bottom of the can swell after it was no longer being compressed by the weight of 4-5 inches of powder above it?

Yep, I know I'd be much better served with a good quality powder measure and definately a better scale, but due to space constraints and the desire for simplicity, I kinda like my current set-up. The finer grained powders, like the AA7, work extremely well with the dippers, but what is it with my Unique?????

Part rant, but mainly a request for knowledge.

Thanks

surv

 

[Olsherm]

I have tried to use the dippers a couple of times but I have found them to be very variable according to how fast or how slow ect you drag them thru the powder.So I still use them to dip with but I weigh every charge regardless. I am just not in that big of a hurry so I weigh them.I get varying weights everytime I use the dippers. Just my experience.

 

[mr surveyor]

A variance of .1 gr to even .2 gr using the dippers doesn't really bother me with my revolver loads, and the dippers measure volume anyway... no different mechanically than any powder dropper, other than being a fixed, non-adjustable volume with the dipper.

I remember following a thread here last year that got downright nasty related to "Lee Dippers", and hesitated to even mention them in my original post. My question is specifically related to the properties of the powder, specifically the physical stability, not the dipper or any other method of volume measurement.

 

[Dale53]

Powder is hygroscopic (absorbs water) so the same bulk will weigh less if it has reduced moisture (kept in a very dry {low humidity} environment. Conversely, if it is extremely humid where you live or more importantly where the powder is stored, it will weigh more.

I have not personally run tests on this as my house including the basement is climate controlled (including humidity). However, tests have been run - unfortunately, I cannot give you a reference (old man's disease, perhaps, but I can't remember the source).

Dale53

 

[mr surveyor]

Powder is hydroscopic (absorbs water) so the same bulk will weigh less if it has reduced moisture (kept in a very dry {low humidity} environment. Conversely, if it is extremely humid where you live or more importantly where the powder is stored, it will weigh more.

I have not personally run tests on this as my house including the basement is climate controlled (including humidity). However, tests have been run - unfortunately, I cannot give you a reference (old man's disease, perhaps, but I can't remember the source).

Dale53

That makes perfect sense. Here in NE TX, we generally suffer from high humidity, and I would normally be more concerned of that "watering down< my powders. Last year, during the late, great unpleasant drought, we suffered through as low as 12% humidity on days it should have been more like 80%. Could very well be that that can of powder has lost moisture?

 

[Dale53]

If you had access to a chronograph you might be able to actually chart the difference. Dryer powders gain strength and wetter powders loose strength.

Powders that are "built" to be volume measured will be affected less by this than powders that are expected to be weighed (in general).

To be honest, I have generally ignored this, personally, simply because I have good storage conditions. I have powders that are many years old that are still giving the same performance as when they were first opened.

>>>Could very well be that that can of powder has lost moisture?<<<

Absolutely.

FWIW
Dale53

 

[mr surveyor]

for overall consistency/reliability, should I invest in a large humidor? That would give me a good excuse to keep more cigars available, as well as storing powders

All jokes aside, what is the preferred storage humidity for stablizing powder consistency?

 

[Dale53]

Humidity inside your home should be between 40%-50%. Powder will store well at that level.

Dale53

 

[Jimbo357mag]

Particle size can play an important roll when using dippers. Rotate the can to mix the powder before pouring into a dish or container to dip from. Also regardless of everything else, I feel like you should be weighing every 5th or 10th charge and comparing the others to that level in a loading block. I would never load a bunch of cartridges and not know how much I was dipping by weight. It's called a safety scale for a reason. 8) 8)

 

[Tellico]

Particle size can play an important roll when using dippers. Rotate the can to mix the powder before pouring into a dish or container to dip from. Also regardless of everything else, I feel like you should be weighing every 5th or 10th charge and comparing the others to that level in a loading block. I would never load a bunch of cartridges and not know how much I was dipping by weight. It's called a safety scale for a reason. 8) 8)

+1---And if you go with the humidor do not enjoy the cigar while weighing the powder. :lol:

 

[mr surveyor]

when you pour a can of powder into your powder measure in preparation of loading a few hundred pistol/revolver cartridges on a progressive press, do you weigh every 4th or fifth throw of the powder? Aren't you still at the mercy of dropping powder by volume, even though you verified the volume/weight ratio for that batch of powder?

I'm just trying to understand the relationship of the powder/moisture content relationship. Is the powder losing necessary chemical properties from evaporation, or is it losing water? If it's the former, then I can understand weight (regardless of volume) being a major variable in the outcome/safety of the load. If it's the latter (loss of water related humidity) then would not the safety factor be edged the wrong direction by loading to weight if the powder has lost some of it's weight from water only?

Thanks for the input.

surv

p.s. I always enjoy my cigars while reloading. I use them for "chew sticks" 90% of the time. I only light one every week or two outside. They last longer as "all day suckers" :wink:

 

[Jimbo357mag]

When using a powder measure to drop powder I still check the weight of the charge about every 10th case or whenever something feels off. With the dippers about every 5th case. Sometimes I weight every load just to be safe.

As far as why there are volume or weight differences batch to batch you got me. Why are there pressure or velocity differences lot to lot? I just know I do all the same checks before dropping powder in the cases and I always check and double check settings and I try and leave some extra margin of safety for those times when things might go a little wrong, like a really hot day or just a tad too much powder.

I think possibly with some powders like Unique with larger gain size the powder can get sifted so finer particles end up on the bottom of a container or pressure can compress the powder or agitation can fluff. Perhaps water content plays a part but I think we don't leave the powder exposed to humidity long enough for it to absorb much water. Perhaps some of the volatiles are evaporating?

To be honest I think the amount of weight difference for the same volume you measured must be some mistake. I didn't calculate, but that is a really large percentage of error for such a small volume measure.

 

[Driftwood Johnson]

A variance of .1 gr to even .2 gr using the dippers doesn't really bother me with my revolver loads, and the dippers measure volume anyway... no different mechanically than any powder dropper, other than being a fixed, non-adjustable volume with the dipper.

Howdy

There most certainly is a difference between between dipping powder and using a mechanical powder measure. Yes, both portion the powder by volume, but the similarity ends there.

With a powder measure you are relying on gravity to dump the powder into a closed container. Once you start to spin the rotor, the body of the powder measure seals the opening in the rotor and the it becomes a sealed container, defining the powder volume by the diameter of the opening as well as both sides.

Dipping is not the same, the dipper is open ended. Even if you scrape the powder level with the top of the dipper, you will always scrape off a few granules as you clear the dipper, leaving a slight hollow at the top corner of the dipper. In addition, consistent dipping is dependent on always dipping with the exact same motion at the same speed to get consistent packing in the dipper. With a mechanical powder measure, particularly if you put in a baffle, gravity packs the rotor and it is much more consistent than the motion of dipping.

I use Lee dippers all the time for Black Powder, because the charges are so large that a 1/2 grain here or there is not significant when dealing with charges of 30 or 40 grains. Not so with Smokeless when just dealing with charges of a few grains.

That's why I never use dippers for Smokeless.

 

[mr surveyor]

I knew I should NOT have mentioned the d*** dippers in the original post.

 

[gerryb158]

There is nothing wrong with using the Lee dippers, if you use them and like them that's fine with me. However, a powder measure (drop) is much more accurate and a much better choice when measuring most powders. The "mechanics" of the measure just make for a much more accurate measurement as explained by Driftwood above. Changes in powder "chemistry" I think are very doubtful. I've read of people using powder that is 20, 30, or more years old with no problems and have done so myself. If the powder is stored in a reasonable environment, original container kept closed and not left open for days or weeks at a time, there should be no problem. Sorry to say but I think your issue is related to the "dippers" and the "technique" used. Consider a measure, (other than Lee) it's a big step forward from scooping! Gerry

 

[mr surveyor]

Again.... take the dippers out of the equation for a moment. Like I said in my original post, I weighed a 1.0 cc "volume" of Unique from a can of powder I've been dabbling out of for a year. Regardless of what Mr. Lee says in his data about a 1.0 cc measure of Unique weighing 9.3 gr +/-, my older powder weighed 7.8-7.9, This was weighed multiple times, as well as double throws on the scale and averaging to find same results. After checking the weight to volume ratio on AA#7, same procedure - multiple single checks as well as averaging double throw, it was within .1 to .2 gr of the Lee data. THEN I opened a new can of Unique and did the same volume/weight measureing procedure...multiple singles and double throw averages, and was finding 8.6 to 8.7 gr.

I was consistantly checking my .357 mag .7 cc loads at 6.3-6.4 gr of Unique out of this can of powder up until late last summer when I decided there was really no need to weigh a known volume that had been verified 8-10 times. That same 6.3-6.4 gr weight for .7 cc would proportionately weigh 9.1 gr in a 1.0 cc volume.

I appreciate all the suggestions to lose the dippers, but I just don't think the dippers could possibly be the factor here. And as far as having knowledge of redundant measurement checks/abilities, my chosen profession of the last 35 years or so has provided that.


surv

 

[Jimbo357mag]

Are we possibly talking about the difference between the old 'dirty' Unique and the new 'not so dirty' Unique? There was a major change in the powder a few years ago. If I remember right all the info said to use the same charge weight but I don't remember any advise about volume.

Do you still have some of the older powder that you can check?

 

[Sal1950]

Dippers or powder measures, they're all the same, they meter powder by volume. Powder "bulkiness" can change with temp, humidity, and how much it's been compressed in handling.
If you want accurate throws and rounds, use a powder measure and test (weight) it's throw every 100 rounds of so.
Either that or get really serious weighting every charge like the bullseye match level shooters do.
Sal

 

[Dale53]

FWIW;
I have met some of the best NRA Bullseye shooters in the country and I don't know a single one who weighs his powder charges. There may be some, but I sure have seen no evidence of that. To remain in shooting shape to be competitive you must shoot a LOT (think in terms of tens of thousands of shots per year). That requirement (unless you are independently wealthy) means you MUST use a Progressive press with it's attached powder measure.

Further, I have met and talked at length with Hall of Fame Bench Rest Shooters and even they, with their MUCH more stringent requirements, use powder measures almost exclusively.

Once you learn which powders measure well (and which to avoid) there is little to be gained and much lost by ignoring a good powder measure. Further, a powder measure is only as good as it's operator. Yes, you DO have to learn to properly use a powder measure.

Dale53

 

[Driftwood Johnson]

Howdy Again

I did not say to get rid of the dippers, I only quibbled with your assertion that they will throw a charge as consistently as a mechanical powder measure will.

That aside, forget the slide rule you got with your dipper set. It is not accurate. I have dipped out Unique, as well as bunches and bunches of Black Powder. The numbers Lee provides with their dippers are not accurate.

And although powder companies strive to maintain the burn rates and other characteristics of their powders over time, they often do change slightly. Some times it is done on purpose by the powder companies. You will also notice over time that a lot of manuals today are recommending lower Max charges with some powders than they did in the past.

Lastly, yes Unique and several other powders were reformulate by Alliant a few years ago to make them cleaner burning. So that may have changed the weight a teeny bit.

Bottom line, just as with a mechanical measure, weigh a few charges to determine what they actually weigh when you dip them with your own particular technique. Forget what the chart says.

 

[mr surveyor]

Howdy Again

I did not say to get rid of the dippers, I only quibbled with your assertion that they will throw a charge as consistently as a mechanical powder measure will.

That aside, forget the slide rule you got with your dipper set. It is not accurate. I have dipped out Unique, as well as bunches and bunches of Black Powder. The numbers Lee provides with their dippers are not accurate.

And although powder companies strive to maintain the burn rates and other characteristics of their powders over time, they often do change slightly. Some times it is done on purpose by the powder companies. You will also notice over time that a lot of manuals today are recommending lower Max charges with some powders than they did in the past.

Lastly, yes Unique and several other powders were reformulate by Alliant a few years ago to make them cleaner burning. So that may have changed the weight a teeny bit.

Bottom line, just as with a mechanical measure, weigh a few charges to determine what they actually weigh when you dip them with your own particular technique. Forget what the chart says.

Just for the record, I'm not trying to be argumentative, or on the defensive here. I just run into a situation I can't totally get me hands around.

The particular can of Unique I'm referring to is "modern".... bought and opened last February. At that time I weighed several single and double "0.7cc dippers" of that powder, and all samples measured around 6.2 to 6.3 gr. I checked this powder several times up until July with the same results, so I stopped worrying about checking what was a known volume, assuming the weight wouldn't vary significantly. The powder is kept in my office/man cave, in as good of controlled environment as most other folks would use. This morning, I checked the powder again with the 0.7 cc measure and found 5.2 gr with a single drop, 10.5 gr with a double drop (5.25 gr ave), 15.8 gr with a triple drop (5.27 gr ave) and 21.2 gr with four drops (5.3 gr ave).

I'm just trying to understand why the volume/weight ratio varied so much on this particular sample.

 

[COR]

I appreciate all the suggestions to lose the dippers, but I just don't think the dippers could possibly be the factor here. And as far as having knowledge of redundant measurement checks/abilities, my chosen profession of the last 35 years or so has provided that.

I HOPE AND PRAY you stop using dippers too...they are gonna drive you and everyone on here trying to help you, CRAZY. You are better suited to measuring every charge...probably due to your "chosen profession for the last 35 years."

Try calling Alliant and maybe they can give an answer that suits you. It's their product, you'll just second guess everyone else to death until you see a chart or something. No answer is gonna suit you 100% without scientific data (for the same reason I mention above).

 

[Dale53]

mr surveyor;
That seems to me to be an extreme variation. I would start thinking other things - like did somehow the powder become mixed with another powder? Did a child have access to your loading room? Most reloaders can remember a time when they either nearly emptied another container into the wrong bottle (most often done when emptying a powder measure back into it's non-original container in error) or really did it.

I would get a large, flat roasting pan from the kitchen (clean and dry, please) dump the whole powder container into the pan and examine it carefully to see if that perhaps has happened. A good magnifying glass can be helpful...

You wouldn't be the first, by NO MEANS...

Just a thought...

Dale53

 

[Sal1950]

mr surveyor,
If you're concerned about the powder with no obvious answers, dump it in your garden for fertilizer and buy a new pound. $20 bucks or so isn't worth the piece of mind or losing a weapon over.
Sal

 

[Lost Sheep]

I'm just trying to understand why the volume/weight ratio varied so much on this particular sample.

Did you ever wonder why rocks keep coming up in your lawn? Why don't they sink down?

Larger granules tend to rise through smaller ones, stratifying your container of powder.

If you don't turn your powder container upside down a couple of times before opening it each time you pour powder out of it, that might explain the different density.

Lost Sheep

 

[Sal1950]

I'm just trying to understand why the volume/weight ratio varied so much on this particular sample.

Did you ever wonder why rocks keep coming up in your lawn? Why don't they sink down?

Larger granules tend to rise through smaller ones, stratifying your container of powder.

If you don't turn your powder container upside down a couple of times before opening it each time you pour powder out of it, that might explain the different density.

Lost Sheep

Shake Shake Shake - Shake Shake Shake - Shake Your Booty - Shake Your Booty :lol:
Sal

 

[Rick Courtright]

Hi,

Been watching this thread since it started, and I don't think anybody's come up w/ the suggestion I'm going to. It's based on the experience I had years ago w/ some "previously owned" powder: Hercules (not Alliant) Green Dot, which I'd loaded umpteen pounds of previously from factory fresh containers.

Mr. surveyor has already done one of the things I was going to suggest by establishing a baseline w/ a known sample, the brand new jug of powder. Ok, now we take that knowledge and apply it to the situation I had...

Which was that this "new to ME" keg of Green Dot--it had been around a long time, under perhaps less than ideal storage conditions--WEIGHED out very light per known unit of volume. Just like mr. s describes w/ his Unique during the summer. So I hand weighed some charges, to the book's starting load. Assembled the ammo, and took it out to shoot.

Whoa! These babies were HOT. And they were SUPPOSED to be only mid-range loads (.44 Mag) There were extraction problems w/ the very first shot in two guns, my RH and a buddy's 629, so we put 'em all back in the truck and they went home to be disassembled.

I ended up reducing the WEIGHED powder charge an additional 10% from the previous starting load (now 20% below book max) and had a pretty good load. But guess what? I then duplicated that load by setting my measure to what I'd used before to get the "normal" starting load by VOLUME. In other words, if 0.7cc was the correct setting from the start, it still was, even though the charge weight was down quite a bit.

I'd experienced similar results w/ Red Dot back when I loaded a lot of it in shotshells. Let's say, for example, a #18 bushing (MEC) would throw the "right" weight from a new canister purchased in the winter. Then, during the summer, as it gets hot and dry around here, it might take a #19 or even a #20 to get the same weight.

But, those "summer" shells were "hotter" just like my .44s were. So I'd go back to the #18 and get the results I wanted, even though the summer shells were now--theoretically at least--loaded "light."

It would be interesting to see if mr. surveyor's loads, using the original setting (dipper or measure, I don't care) to duplicate that original VOLUME (forgetting its absolute weight), would still perform to spec? If his experience is like mine, they just MIGHT!

BTW, there's never been a powder chart I've ever seen, regardless of who printed it, that comes close to what we'll get in the field. They're just a guide to get to a starting point. W/o a scale, you're flat lost...

Rick C

 

[DGW1949]

So Rick C, are you saying that if/when we begin to see that the weight of a certain volume of powder begins to decrease, that it's better to load by volume instead of weight?
If the answer to that is yes, then how does one verify the accuracy of his measured charges when he can no longer trust his scale? Or to put that question another way....without knowing the climatic conditions that were present where/when the manual got writ, how would one know that the X-amount of grains in the manual is the same as the X-amount of grains that he see's on his own scale on the day that he see's it?

20% is a LOT of variance in volume. The implications of that are tremendous.

DGW....who hopes he misunderstood your post.

 

[Rick Courtright]

So Rick C, are you saying that if/when we begin to see that the weight of a certain volume of powder begins to decrease, that it's better to load by volume instead of weight?
If the answer to that is yes, then how does one verify the accuracy of his measured charges when he can no longer trust his scale? Or to put that question another way....without knowing the climatic conditions that were present where/when the manual got writ, how would one know that the X-amount of grains in the manual is the same as the X-amount of grains that he see's on his own scale on the day that he see's it?

20% is a LOT of variance in volume. The implications of that are tremendous.

Hi,

I think there's a compromise position in there, kinda based on the "start low, work up" mentality we've used forever.

The way I see it, if the powder changes density, either seasonally or just over time in general, it's because some kind of moisture is being released or absorbed. Now, that could be simply water, which makes sense to me if "hot and dry" conditions produce a lower density than "cool and moist." To a certain degree, THAT moisture will return when the weather changes back.

Or it could be volatile elements of the powder itself. I don't know what they do, how they do it, or how important they are. But I suspect that as they're lost, the powder becomes "hotter" by unit of weight. This is the situation I suspect w/ that one lot of Green Dot that I didn't obtain new. Whatever these volatile elements are, they're not coming back once they've evaporated out. Think, for example, of paint drying?

Now, w/ those ideas in mind, the base line approach is critical the way I see it: we have to establish how many cc of ABC powder it takes to get x grains, straight from the factory. So we use the scale, set the measure, do our test firing to determine the load that works for us. That's what I believe mr surveyor did when he determined that 0.7cc averaged around 6.2 gr from his fresh container.

Once we have that baseline, then we can tell IF the density is changing. And that's what he found when his 0.7cc measure (dipper) started throwing a considerably lighter charge over time.

The problem I found for myself was that I was believing my scale, as we should, BUT I wasn't weighing the "same" powder I would have if I'd just opened the factory jug. What I was weighing was less dense, just as mr surveyor found w/ his.

Ok, what to do now? Believe the scale? Believe the volume setting that has worked before (w/ THAT lot of powder, of course!)? Or something in between?

If it's true powder does become "hotter" as it dries out, then it seems prudent to move toward the volume measure. That way, we still get the same amount of "solids" as we would have earlier w/ a heavier charge. We're just missing the stuff that evaporates.

None of this is cut and dried, of course. Part of it depends on the powder itself: the only instances I've personally experienced this w/ were flake powders from Hercules/Alliant: Red Dot and Green Dot. Add mr surveyor's experience w/ Unique and we're talking another flake powder from the same mfr.

If we look at ball powders, or stick powders, I've never seen the kinds of density changes I have w/ the flakes. They seem to retain their factory density much better over time. For example, I've still got some Win 540 and Win 296 that are both well over 25 yrs old, and they weigh out the same (per unit volume) as they did the day I opened 'em. Perhaps some folks have seen them change, though. I dunno...

So I guess what I'm saying is to remain vigilant and don't ignore the relationship between volume and weight. So when the scale tells you a certain volume's starting to weigh in light, start watching carefully for signs of changes in your ballistics, and back down appropriately as required.

For example, if mr surveyor takes ammo loaded w/ the "original" weight, right from the new container, then later had some loaded w/ the same volume but "reduced" weight, and put both over the chrono and gets similar results, we'd be able to suggest volume is important for THAT load. OTOH, if the results showed a proportionate drop, we'd know weight is the important consideration, again for THAT load.

Remember, this is just one person's experience, so please don't take it as advice w/o doing your own testing! YMMV, "In MY gun" and all those other things...

Rick C

 

[Donaldjr1969]

For what it's worth, I tend to use dippers myself, but not for the total charge weight. When I am loading up small amounts of ammo, such as 12-18 rounds, I use a dipper followed by the powder trickler to get my charge. Much faster than filling my powder measures (I have a Lyman 55 and a Lee Autodisk, the Lee being spot-on accurate metering American Select), setting the charge weight, then dumping the powder once I am finished. Yesterday, I loaded up 10 rounds for my .500. I got 3-5 done using the dipper furnished with my Lee dies for the .500 and the powder trickler to measure 42g H110 by the time it would have taken me to fill the Lyman and set it...