Size and shape of modern gun powder


#1

I asked this question a long time ago. The collective consensus/answer was “it is what it is”, that different companies in different countries during different times came up with production processes which resulted in different shapes, so “live with it”.
I decided to re-phrase my question. In the present time, with supercomputers capable of predicting and foreseeing phenomena of the distant future, is it yet known which shape and mass of a gun powder particle is the best for a certain in-cartridge pressure? For instance, maybe for rifle ammo the particles of spherical shape 0.5mm diametre are the best? Surely, mass/density/external surface ratios influence degree of burning and thus expulsion of the bullet. The gun powder mix in the picture are old batches from various multi-country ammo, just to illustrate my question about different shapes etc.


#2

I am thinking that the size and form of powder granulations can only be optimized, not perfected, because powders are made to work in a variety of cartridges. A powder that is developed to work at an optimum level in only one cartridge may be technically possible, but it is probably economically unfeasible. Just as a guess, I would think that perfecting granulation size and shape yields diminishing returns when a powder is designed to be used across a spectrum of cartridge classes and that doesn’t even take into account the variations in weapons the ammunition will be used in.

From another view point, the manufacturer has several criteria that can be emphasized or discounted when developing a powder. The first problem is going to be the definition of “perfect”. Does perfect mean highest velocity, highest accuracy, absolute safety or ease of manufacturing? I have never researched the problem of granulation shape in smokeless powder, but it could well be that all of the common current designs work well enough that there is little gain to be had, or money to be made in seeking perfection.

Curt


#3

All of the reasons why certain powders are different shapes, and with different sizes of granules, and different coatings, and different chemical properties and proportions, would fill a very large book and probably contain chemical formulas and mathematical equations beyond the understanding of the average shooter or cartridge collector. That is why graduate engineers in various fields make up part of the work force of ammunition and ammunition-component factories.

The subject is probably beyond any truly comprehensive answer that could be given on this type of forum. That is probably why the answer “it is what it is” was given here.

I know that formulating specific powders to specific burning rates is very important. I also know that there are just everyday practical reasons why some powders are made the way they are. The powder I use in my Cowboy Action Shooting loads, Train Boss, is a good example. I will not discuss loads here - it is against the rules of the Forum and for good reasons - but I can say that Cowboy Action shooters often shoot very light loads in cartridge cases of, for pistol ammunition, very high powder capacity. That can be a disaster called “detonation” waiting to happen. Trail Boss was especially formulated to be very, very bulky. Loads that will not detonate due to volume and fill the cases, which generally gives good ignition and good accuracty all other things being what they should be, are possible at pressures that will not begin to overstress even the old designs of firearms used in CAS. It is only one example of the science of manufacture of gunpowder, but one recent enough to show that the science continues to progress as new challenges arise.

If I say much more on the subjects which I am familiar with, I will be treading in dangerous water regarding the discusion of reloading. Perhaps fortunately in this instance, I am ignorant of the real technical and scientific factors involved in this subject.

I do not think I have crossed the line regarding the topic of “reloading” with this answer, but if the moderators believe I have, please simply delete this entire answer. It probably will not satisfy most anyway.


#4

Vlad’s question is a very good one. But I don’t think anyone has answered it. Yes, we all know about burning rates, loading densities, etc etc, but I have the same question as Vlad. Why does one manufacturer make his powder in the form of flakes and another in the form of sticks?? Both produce the same ballistics in a given case size so why are they different??

I can only guess that maybe it has to do with materials that a manufacturer has available to him and the types of equipment that he has to produce the powder. Maybe one has access to the finest grade of cellulose while another may have to settle for lesser quality ingredients. One has equipment set up to produce stick powder while the other is best suited to making flakes.

Black powder is a mechanical mixture of 3 basic ingredients so anyone making it uses the same methods as everyone else and the products all look the same. Smokeless powders, on the other hand, are chemical compounds and the manufacturer has to manage and control the process as he knows best and his equipment allows.

Bottom line Vlad, it is what it is. ;) ;)

Ray


#5

The simple answer is its all to do with surface area v volume. Take two one yard square chunks of wood. Render one down to matchwood, cut the other into six inch cubes. Then set light to both piles, the matchwood will be consumed in minutes, the six inch cubes will still be burning an hour later. The only difference is surface area since its the same wood from the same tree.

The other consideration is the need to meter faultlessly through all kinds of loading machines. Stick powders are common because the powder is extruded like pasta. Some powders are hollow sticks exactly like pasta to increase the surface area even more.

Different manufacturers approach these things in slightly different ways. Flake powders are rolled to flatten them, the degree of flattening increases the surface area.

In recent years a lot more has been achieved with retardents and accelerents in the mix to achieve different burning characteristics


#6

Vince

This may answer Vlad’s question, but not mine. We’re back to talking burning rates, powder densities, etc. My question was, why does one manufacturer load a 7mm Mauser with 42 grains of a flake powder while another loads theirs with 42 grains of a stick powder. A third may use 42 grains of a spherical powder. All three result in the same ballistics.

So, why the different powder shapes and sizes to acheive the very same result? I don’t think there is an answer. That’s just the way it’s done. The same reason a Remington case may have case wall thickness of .029" while an RWS case may be .031" at the same location. Or why some cookies are round while others are rectangular, or oval, or square. ;) ;)

Or, maybe it’s the Chaos Theory at work???

Ray


#7

Ray you are right partly because there are so many powders on the market now and different manufacturers clearly approach the problem from different directions.
We are not allowed to discuss reloading but I know you reload and so do I. It would not be possible for you or I to even dent the range of powders available in several lifetimes of serious evaluation, even if our bank balances could stand it which is doubtful. So now it is chaos theory. This has evolved far beyond the point where you could describe it as saturated. fifty years ago it was very different. Only a handful of powders on the market yet they still achieved good groups and scores.

And more powders are appearing on a weekly basis, you have to question what they are trying to achieve.


#8

How many different types and sizes of car oil filters are there? And why are more than a just a few needed?

In fact, maybe a half-dozen different smokeless propellants would cover almost all small arms ammunition loading requirements - maybe not optimally, but adequately for most purposes. Instead there are hundreds. I remember George Frost’s comment that Bullseye could be satisfactorily used for almost any non-magnum pistol cartridge of any caliber. And I have done that myself.

Regarding detonations, there have been some incidents in which detonation may have occurred in some rifles in which very light loads of very slow propellants were used, but those could not be replicated. Seems like the caliber involved was 6.5X55. Light loads of fast burning pistol propellants in large capacity cases may cause erratic performance and inaccuracy, but I have never heard of anything like a detonation resulting from the practice.


#9

I fear I am treading on forbidden ground…Double base powders under certain conditions will detonate as opposed to a high pressure deflagration. The .243Win and 7mm Rem Mag are prime candidates for for this phenomenon. Light loads of slow propellant and a light projectile and a longer than average barrel can (several other factors can also contribute, worn throat, etc.) be disastrous.


#10

AccurateRifle.com had a wonderful April Fools Joke this year for the obsessive/compulsive handloader: a powder grain perforation uniformer.