[dbooksta]

Is there any research or history of loaders blending propellants to improve ballistic performance?

Hornady appears to be producing higher velocities without increasing charge weight in their Superformance ammo by using "progressive propellants." As best I can tell this means they are blending propellants with different burn rates in order to sustain peak pressure over a wider interval of time.

In theory this seems like a great idea: Since peak pressure of a homogeneous powder in a particular loading generally only lasts for an instant, we can stretch out the duration of peak chamber pressure by combining powders that reach their peak at slightly different times. (The longer the pressure peak is maintained, the longer the bullet enjoys peak acceleration, and the faster the muzzle velocity one would expect. One could also expect, as Hornady claims, that felt recoil would decrease since propellant efficiency is effectively increased, reducing rocket effect.)

In practice I imagine this would be difficult and dangerous to achieve without access to precision pressure-transducer barrels to work up the loads while being able to observe the timing and duration of pressure peaks. After all, even if you know the pressure curve of a single propellant in a particular load I doubt it's safe to conclude that blended propellants produce pressure curves that are just the sum of their curves in isolation.

 

[264shooter]

There have been reloaders that used duplex and triplex loads,Most layered 2 or 3 powders in the case usually with the faster burning powders closest to the primer.I am not aware of anyone blending 2 or more powders of different burning rates but I would imagine someone has tried it.Hornady did not blend any existing powders.They reformulated powders to get the results they wanted.

 

[kdub]

Knew a guy that decided to load a bit of Cadweld powder in his handgun loads. Cadwelding is the process by which you can braze wires or such to metal. We used it to attach anode wires to pipelines. Long story short - he managed to weld the cylinder to the barrel and frame of the handgun. Also, eroded channels in all.

PLEASE - let's not have anyone trying to mix powders trying to increase performance!!!!!

 

[unclenick]

It doesn't work out theoretically. Suppose, for example, you use an equal volume of fast, medium, and slow powders. Let us further suppose, for theoretical purposes, that each powder had a bulk density that they just filled the case under the bullet when loaded to normal peak pressure individually. In other words, the fast powder was high bulk, the slow powder low bulk, and the medium powder somewhere in between. In the blend, if the case is filled, each powder now has a third the amount you could fit in the case if they weren't blended. So each is only able to contribute to about a third of the peak pressure they would have created stand-alone. Thus, if you succeed in stretching out the pressure peak out it will be at the expense of it being a lower pressure peak than it was with any one of the powders individually.

Modern rifle powders are all progressive. This means they generate gas more and more rapidly as they burn (the gas evolution rate progresses with the burn, hence: progressive burning powder). They can only succeed up to a point, however. The remaining portions of the burning grains eventually get so small they are generating gas more slowly as they continue to burn. That means the gas evolution rate digresses. In other words, the powders switch from progressive to digressive burning. This happens where the rising edge of the pressure peak starts to flatten out.

Hornady claims is the powder in their new loads is super-progressive. I don't know what that means? IF they were simply a blend of conventional progressives highly compressed or whatever, the recoil would increase because slow powders maintain late barrel time acceleration by maintaining barrel pressure late in the burn. At the muzzle that added pressure contributes to rocket effect.

Another possibility is they have come up with some new powder formulation that skips most of the digressive burning stage after the peak, instead burning up practically everything by the end of the peak? That way, they would let the longer peak do almost all the accelerating, but not have increased muzzle pressure to contribute more rocket effect.

If that's how they are doing it, it will be easy to tell. Without added acceleration late in the barrel time, having a longer barrel should increase bullet velocity less than it does with standard loads.

 

[dbooksta]

It doesn't work out theoretically. Suppose, for example, you use an equal volume of fast, medium, and slow powders. Let us further suppose, for theoretical purposes, that each powder had a bulk density that they just filled the case under the bullet when loaded to normal peak pressure individually. In other words, the fast powder was high bulk, the slow powder low bulk, and the medium powder somewhere in between. In the blend, if the case is filled, each powder now has a third the amount you could fit in the case if they weren't blended. So each is only able to contribute to about a third of the peak pressure they would have created stand-alone. Thus, if you succeed in stretching out the pressure peak out it will be at the expense of it being a lower pressure peak than it was with any one of the powders individually.

Here is the scenario I had in mind: Take powder #1 that achieves SAAMI max allowed pressure (MAP) with a half load at 1ms, and has dropped to half MAP at 1.5ms. Add powder #2 that peaks later -- half MAP at 1.5ms, achieveing full MAP with half a load at 2ms. If blending the two did not affect their burning characteristics in this load, then one might discover that a near full load of an equal-volume blend of these powders reaches MAP at 1ms and holds it past 2ms, which could produce far more acceleration than a conventional powder that only hits MAP for an instant.

It also seems plausible that this would produce higher velocities with lower rocket-effect recoil than a homogeneous slow powder that drops off its MAP more slowly than either of these faster powders or their blend. (The slow powder could compete on muzzle velocity only by maintaining higher average pressure than the fast powders, but if it does that it will by necessity produce more rocket effect because it's compensating for lower time at MAP by increasing propellant volume later in the game.)

 

[Carpe Diem]

The "rocket effect" depends entirely on the mass of powder and its velocity at exit - the latter almost directly proportional to muzzle pressure. To reduce that effect you need to either reduce the charge weight, or reduce muzzle pressure. But the latter goes against the common effort to increase velocity by keeping pressures higher throughout bullet's travel. All smokeless powder is "progressive" which means it burns in a controlled manner, unlike black powder, which effectively detonates. Hornady is certainly not immune to producing effective hype - don't assume that they use any particular method to achieve their performance.


.

 

[mattsbox99]

Slow powders like RE25 already fill the case as full as we can get it, there would no more room for another slow, medium, or fast burning powder.

The bottom line is that we can not get every powder available, and not every load is published that would work, heck, even RE25 would work in a 25 ACP, not very well though.

 

[qajaq59]

Plenty of people have done it, but I certainly wouldn't. Too much to lose and not enough to gain.

 

[Rocky Raab]

I cringed when I read Hornady's description of their process, because I just KNEW that the first thought in some minds would be to start mixing their own powders.

DON'T!

Not to put too fine a point on it, but neither you nor I are smart enough to even attempt this. We don't know the exact chemical or physical properties of any of our powders. Nor do we have the test equipment to monitor results of experiments.

To paraphrase something I read, the interval between trigger and tragedy is far too short to change your mind.

 

[wyoman]

+1 on what Rocky said. As soon as the new Rifleman came and I read that article, I have been wondering how long it was going to be before someone ended up being a news story. I wish in the article they had just stated that they had formulated new proprietary powders for their new ammo and left it at that. In todays world even the words you speak sometimes have to be based on the lowest denominator.......in I.Q.'s

 

[unclenick]

It's not about I.Q.'s. The curious will always stick their necks out to some degree to try things. More at fault, IMHO is publishing a partial description of the process without the potential problem areas being mentioned. Some of the interactive considerations needed to do the development work successfully and safely are just not going to occur to the causal experimenter.

. . . If blending the two did not affect their burning characteristics in this load. . .

That won't happen. The higher the pressure the faster powders burn. If you use a quick powder to build pressure earlier, the slow powder will now be burning faster and earlier in the total volume expansion than it does when used by itself. That's what makes this complicated. You can't just sum up the pressure curves of the two contributing powders. You'd need to have good pressure test gear and do the blending cautiously to keep your pressure gun alive.

You'd probably also need to use constituent powders of close to the same grain size and density so the mix doesn't tend to separate during transport vibration or even in your powder hopper. Woe be to the fellow who uses a low bulk density stick for one burning rate and a dense fine spherical for the other. Even if it didn't stratify, the fine grains lying in the spaces between the coarse grains would change the coarse grain's ignition characteristics all by itself. It's just not a trivial problem to solve.

 

[Rocky Raab]

Lest some folks be outraged and insulted, when I say "smart enough" in this context, I mean "educated enough." Not IQ, but education.

 

[dbooksta]

Let's try this again. I'll start my question with the disclaimer that I originally posted at the end:

In practice I imagine this would be difficult and dangerous to achieve without access to precision pressure-transducer barrels to work up the loads while being able to observe the timing and duration of pressure peaks. After all, even if you know the pressure curve of a single propellant in a particular load I doubt it's safe to conclude that blended propellants produce pressure curves that are just the sum of their curves in isolation.

And now I'll repeat the question:

Is there any research or history of loaders blending propellants to improve ballistic performance?

I'm not planning to blend my own powders anytime soon. But I would also be surprised if no manufacturers or researchers (admit to) produce or use any heterogenous powders. Given the potential benefits of stretching out the burning duration at maximum pressure, and given that the only way to do that would seem to be with a blend of powders with different physical and/or chemical characteristics (per my earlier example), I am left wondering what the real story is with this.

 

[VdoMemoriie]

Greetings to all of you, this is my first post here and I had asked this question in another forum only to get some one mad at me.
I keep thinking of mixing Blue Dot with A Steel 50:50 and feel you could custom tailor a certain effect with the ratio or even 40:60
and get the best of the two powders.This could be easily done with small amount of powder like 50 grs of each and mix it.
I am guessing some of the big companies selling very high speed sabot loads
could be mixing powders as http://www.bsn.it/prodotti/images/modSu ... ng_web.pdf
these high speed shot shell loaders can not load duplex or even triplex loads, thats why I feel that maybe they might be even mixing powders to achieve the effect they want. They have all the testing equipment and its no big deal for them.
Ed I know you did some duplex loads in the past, and as far back as late 70's and 80's some shooters were using duplex and even triplex loads in big bore hand guns.
The above machine is capable of 7000+ loads an hour.
All I can say is I wish
Looking forwards to hearing your take on this matter.
Ajay Madan


Edit: Links not permitted in Signatures

 

[mattsbox99]

That is extremely unsafe...

 

[Rocky Raab]

Well, if you sight down the rib and then wake up in intensive care, you'll know everybody else was right.

 

[gunpa]

Dick Casull did it when he and friends developed the 454, but I believe he also had access to pressure testing equipment and seriously overbuilt revolvers when he did it. Most of us don't have those resources or the necessary expertise. I wouldn't want to blow up a good gun or myself trying such things. I'm dangerous enough as it is. I won't elaborate on that.

 

[MZ5]

The scenario that unclenick described in his first post (powder not switching from progressive to digressive, but staying progressive. Or at least not becoming so digressive) is essentially what I read that Rifleman article to describe. I believe they described a propellant that built pressure, then the peak was flattened vs. what they've done before, and then the digressive burn was reduced (i.e. less digressivity) as pressure dropped such that muzzle pressure was noticeably lower than what they've loaded before. This would reduce rocket effect, hence lower 'recoil.' And that's exactly what the article described, the way I recall it. They also described less of a difference in velocity with barrel length differences vs. other ammunition.

Theoretically, I think this would require a powder which experiences 'normal' (for the cartridge) to relatively rapid pressure rise until a certain pressure area is reached, at which point something retards the burn rate somewhat (relatively speaking) so as to maintain a flatter pressure curve. Then, as pressures decline, that retardant effect is reversed and the remaining powder burns increasingly quickly so as to drop residual pressure (reduce muzzle pressure).

One wonders: Could coatings be added to a powder to achieve this?

Let's suppose it's all the same base powder in use rather than the speculation I've read on various sites up until now that it'd be fast + slow powders, or fast + medium + slow. What if two quantities of the identical underlying powder (forgive me if I'm using improper terminology here) were additized with completely different coatings? Let us suppose that the coatings acted in roughly opposite ways, such that portion A's coatings caused it to burn increasingly rapidly as pressures rise, while portion B's coatings cause it to burn increasingly slowly as pressures rise. In this way, A would burn faster as pressure increases, while B would burn faster as pressure decreases. Could this basic design premise be 'blended' (to use the article's vernacular) to achieve what Hornady claims?

I can think of other alternatives concerning porosity at the surface of the granules vs. in the center of the granules, but coatings should be easier to manufacture and apply, I would think, than a super-complex granule structure like this.

Remember that the difference between the pressure traces shown for the Superformance vs. Light Mag. (and 'regular') ammo aren't huge, though they apparently are different enough to make a noticeable difference at the muzzle.

 

[MZ5]

Let me try to re-phrase a portion of what I just posted. The theoretical coating(s) that I reference would be in addition to whatever are used in the basic underlying powder. So, we'd start with let's say a 4350 for a heavy 30-06 load. We'd have 2 quantities of that 4350 which would be further additized to exhibit the opposing properties I described. Hope that hasn't made things more muddled.

Also, I agree with unclenick's second post as to where the irresponsibility lies concerning lack of information provided in the article and potential home experimentation of a completely improper and unsafe sort.

 

[VdoMemoriie]

Greetings to all of you.Those shotshell manufacturing machines can only dispence one type of powder while loading and therefore can not produce Duplex loads even if you want to load two powders in layers. Thats why I feel they might be mixing powders in another division that does that mixing just to get a certain effect of ignition.
No big deal for them and even handloaders were doing Duplex and Triplex loads in the late 70's and 80's for Big bore hand guns.
Here's an example of that for 454 Casul Unique was the starter powder followed by 2400 powder and then topped by Bulseye or Unique.
No production machine can load this, but only a handloader can in this case.
I agree it can turn into a desaster if one is careless and does not do his home work to verify, after all no matter what any one says we are playing with fire!
Trust but verify ( R.Regan )
Greetings and Happy Holidays to you all.
Ajay Madan


Stop inserting link to your photo business. 3rd warning. Next step is being banned from board. Kdub - Moderator