Case chemistry and/or physics?

Most likely a typo in their notes. Pressure and velocity are directly correlated in their relationship. Can't have one without the other.

Demi-human said:

Most likely a typo in their notes. Pressure and velocity are directly correlated in their relationship. Can't have one without the other.

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This is no typo, the article “Starline Brass” is in the Aug 2017 issue of Handloader; and the author, Brian Pearce, expands on this, stating that some ammunition company and a powder laboratory found that Starline brass allowed standard velocities, but at pressures as much as 10,000 psia below maximum average guidelines.Whatever that means.

A claim like that should have been challenged by the Gunwriter and the publication which prints it. This is an extraordinary claim, that you can at the same time keep to a standard velocity but greatly reduce pressure just by a change of brass manufacturer. As someone wise said, extraordinary claims need extraordinary evidence. We don’t know what is behind all this hoopla, and if we did, I am certain that there is some clever trickery going on behind the scenes.

One of the first things to require is to require an explanation of how this works. We do know that changing case volume will alter pressure, as for example, greater case volume will drop pressure somewhat and we know greatly reduced case volume will greatly increase pressure. Maybe they are altering case volume and using a greater volume of slow burning gunpowder, something like that. The article said nothing about the characteristics of the gunpowder being used, that is a good candidate for the rabbit in the hat.

There is always the potential that someone’s instrumentation is messed up. Happens all the time, this is why in science extraordinary claims have to be independently verified by test, before the science community accepts things. Anyone remember Cold Fusion, Stanley Pons and Martin Fleischmann? https://en.wikipedia.org/wiki/Fleischmann–Pons_experiment The half life of a research article is seems to be around three to four years. https://scholarlykitchen.sspnet.org/2013/12/18/what-is-the-lifespan-of-a-research-article/ This is due to a problem called non-replicability. Psychology is particularly bad, less than half of all psychology studies have replicable results, http://www.apa.org/science/about/psa/2015/09/low-replicability.aspx, and in time, when researchers figure out a study is un reliable because its results can’t be duplicated, studies slowly stop being referenced. No one is actively debunking non replicable studies because debunking is unprofitable. Regardless, Handloader should have printed data backing up the claim, but as gun magazines always do, the sources are non attributable and the data never presented. Basically, industry gossip.

I recall the wildcat era where gunwriters uncritically repeated the velocity nonsense of wild cat cartridge creators. American's want the most horsepower and the fastest, most powerful cartridges. The claims of the period that certain characteristics of wildcat cartridges created higher velocities fizzled once shooters were able to buy cheap chronographs. The great velocity increases just did not reveal themselves over the chronographs. There were velocity increases, but maybe 25 to 50 fps at most, if pressures were kept to industry standard. The wild catters were claiming velocity increases of at least several hundreds of feet per second. We have not gotten to cheap and easy pressure gages, but it is beginning to be understood that the great wildcatters, such as P.O Ackley and Weatherby really got their higher velocities through operating pressures 10,000 to 20,000 psia above industry standard pressures. At the time Ackley was claiming that the secret was straight walled cartridges, Weatherby claimed it was because his venturi shaped shoulder burned the powder so efficiently.

I model gun articles in print media as advertisements, and gunwriters as low paid temps for corporate advertising bureaus. I think the claims of the article reinforce an impression that in print gun magazines and their writers are shills for the industry. They don’t have the critical analysis skills to challenge what industry tells them, and they don’t want to, because it might affect advertising revenue. Gunwriters have gone through a Darwinian selection, in which for little pay, gun writers are selected based on the ability to create an interesting story and repeat uncritically, everything the advertising department tells them. There is very little difference between a gunwriter and a trained seal. They will both get up on a box and bark for a fish.

The whole article Starline Brass is a nice puff piece, Starline does make good brass, they are now branching into rifle brass, but I don't believe that Starline brass transcends physics without more definite proof.

Slamfire said:

Starline does make good brass, they are now branching into rifle brass, but I don't believe that Starline brass transcends physics without more definite proof.

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Precisely. A change of powder may be able to effect a change like that, but not merely changing the case, ostensibly made to the same specifications as the previous cases from differing manufactures.

It was that a human had not to believe advertisements, now it is to find what is advertisement and what is not. And yet some are chastised for using the term 'Fake News'. We in the firearms community are completely accustom to it already, and can filter it out, with only very little critical thinking. If only this would "rub off" on some other groups of populace.

Slamfire said:

This is no typo, the article “Starline Brass” is in the Aug 2017 issue of Handloader; and the author, Brian Pearce, expands on this, stating that some ammunition company and a powder laboratory found that Starline brass allowed standard velocities, but at pressures as much as 10,000 psia below maximum average guidelines.Whatever that means.

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You're a lot faster on the keyboard than I am Slamfire.

Typo was my first guess too, but after re-reading the paragraph several times, I decided it’s no typo. And I don’t understand it, nor can I find anywhere in the article where the author explains higher velocities with “significantly less pressure” using Starline .357 and .44 Magnum cases. But the author (Brian Pearce) goes on to claim that because of the tests, the ammunition manufacturer doing the testing “began using Starline cases almost exclusively.”

As the OP stated, the article is in “Rifle’s Handloader” magazine. It’s in the August 2017 edition, and it’s titled “Starline Brass” by Brian Pearce.

I couldn’t be happier with Starline brass, but this sounds like magic.

Never believe anyone trying to sell you something

The only way I can think would be to change the geometry of the inside of the case in a way that would change the P/t curve.

Same internal volume, different shape... ie, cone vs hourglass.

Demi-human said:

Most likely a typo in their notes. Pressure and velocity are directly correlated in their relationship. Can't have one without the other.

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changes in friction and/or inertia can increase one and decrease the other. i believe the article says that a special heat treat is what does this.

murf

jski said:

Someguy2800, this is suppose to be a unbiased presentation ... not a sales pitch.

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Yep, supposed to be but it sounds kinda weird; lower pressure and higher velocity from a particular brand of brass???

murf said:

changes in friction and/or inertia can increase one and decrease the other. i believe the article says that a special heat treat is what does this.

murf

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I do not receive this magazine. Could you please elaborate on this.
The way I understand it so far, more friction, such as using jacketed as opposed to lead, increases pressure. Using more inertia, such as a heavier bullet, increases pressure.
Do I understand this correctly? (Not just murf, anyone may enlighten me.)

Slamfire wrote:
I don't believe that Starline brass transcends physics without more definite proof.

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It's a function of the unobtainium they mix in with the copper and zinc.

Seriously, you wrote a very well organized post that was a pleasure to read.

Demi-human said:

Most likely a typo in their notes. Pressure and velocity are directly correlated in their relationship. Can't have one without the other.

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Happily can have lower pressure and greater velocity if you have a larger volume.

I do not receive the magazine either. It is difficult to draw conclusions, either way, when I see only partial descriptions of a casual magazine article.

Like others on this thread, I tend to withhold judgment pending verified data, rather than purchase ownership in everything I read.
Don't get me wrong, I read magazines and I read posts on Al Gore's invention The Internet. But I'm selective when it comes to belief.

We could fill a dump truck with everything I've heard at gun counters, or read in magazines, that die a quiet death unverified.

Demi-human said:

I do not receive this magazine. Could you please elaborate on this.
The way I understand it so far, more friction, such as using jacketed as opposed to lead, increases pressure. Using more inertia, such as a heavier bullet, increases pressure.
Do I understand this correctly? (Not just murf, anyone may enlighten me.)

Click to expand...

wolfe publishing will sell you the current issue of handloader magazine, which has the "starline brass" article. ph: 928-448-7810, or www.handloadermagazine.com .

the only way the case can have an affect here (besides a bit of an increase in case volume) is case neck tension on the bullet and the amount of pressure it takes to release said bullet. increasing the time it takes for the bullet to get started down the barrel would have a significant effect on pressure and velocity. maybe starline has found the right combo of brass type and annealing of their cases to reduce pressure while increasing velocity. (increasing/decreasing case wall thickness won't work here due to case dimension restrictions)

the only way to prove this claim is to load up test rounds using starline brass and "other" brass, shoot them in a test barrel, record the pressure and velocity, and compare the results. i would assume starline has already done this. but, who knows.

murf

Varminterror said:

..if you have a larger volume.

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Yes. In which to put more powder.
But then a thirty eight super isn't really a nine milimeter. Evidently a product placement article.

I thought I was missing some new technological break though. A man can only have so many 'references' and I find this organization to be the most fruitful one. It saves a lot of trees too.

It's surprising how much difference a little volume makes - I've been using FC brass for many years in 223rem, I get about a half grain more in the case before I get the same pressure signs as I would with a lesser charge in Win/Rem/Hornady brass. That half a grain means more velocity. Put that same charge into win/rem/hornady brass and I get immediate pressure signs on primers, brass, bolt lift, and/or ejection. That's more pressure. More volume, lower pressure to get the same velocity, or same pressure to get higher velocity.

Thank you kindly @Varminterror . I appreciate the knowledge. I ran out some numbers, using your experience. In my own rifle, a gain of a half grain would increase muzzle velocity by fifty eight feet per second. Equating to four less inches of drop for a seventy five grain bthp at six hundred yards.
This surprised me a lot. As a half grain is only two hundredths percent more powder for my load.
Pistols have my attention lately, but I will soon be water volume wieghing some brass for the Savage.

Thanks again.

murf said:

The only way to prove this claim is to load up test rounds using starline brass and "other" brass,
Shoot them in a test barrel, record the pressure and velocity, and compare the results. I would assume starline has already done this. But, who knows.
murf

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As mentioned above, we would need to see more specific information to evaluate the claim.
Our gun magazines (I've got almost a dozen subscriptions) are known for hyperbole and sensationalism, just like all the world's media.
It's interesting to read it, but wait until you make sure the flavor before you drink the whole glass of Koolaid.

Don't forget, my friends. A half grain of brass in a revolver case is a teeny tiny sliver. A half grain of powder needs a lot more space.
Reducing the brass by a half grain in a revolver case doesn't get you another half grain of powder.
Like Varminterror, many of us seek rifle brass with greater capacity. It's a known strategy, you bet!
But for revolver brass (as quoted in the article) you don't get a big volume increase.

ants said:

As mentioned above, we would need to see more specific information to evaluate the claim.

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If it means anything to anyone, I have already sent a snail-mail letter to Wolfe Publishing requesting that Brian Pearce provide more "specific information" about his claim. I'm not holding my breath waiting for a reply though.

ants said:

As mentioned above, we would need to see more specific information to evaluate the claim.
Our gun magazines (I've got almost a dozen subscriptions) are known for hyperbole and sensationalism, just like all the world's media.
It's interesting to read it, but wait until you make sure the flavor before you drink the whole glass of Koolaid.

Don't forget, my friends. A half grain of brass in a revolver case is a teeny tiny sliver. A half grain of powder needs a lot more space.
Reducing the brass by a half grain in a revolver case doesn't get you another half grain of powder.
Like Varminterror, many of us seek rifle brass with greater capacity. It's a known strategy, you bet!
But for revolver brass (as quoted in the article) you don't get a big volume increase.

Click to expand...

starline's annealing method is proprietary, so i doubt any info will be forthcoming. if other ammo makers "drink the koolaid" and purchase starline brass for their premium ammo, there may be something to this "less pressure/more velocity" claim.

a 45 long colt case has plenty of space for that extra half grain. case weight has nothing to do with powder capacity, it has everything to do with initial case volume. not many loads (pistol or rifle) are at 100% load density, so another half grain of powder will fit. again, initial case volume is what is important here. as varminterror said above, you can increase velocity and decrease pressure if you increase the internal volume of the case.

i don't think this is the path starline has followed. there is not much room to grow case volume if the manufacturer follows saami case drawing dimensions. i still think they have done something to their annealing process.

murf