S.E.E. loading data, need help

[Mr Humble]

There was quite an exchange here on SEE (secondary explosive effect) that lead to a banning. As the subject was left hanging, I wish to test the hypothesis further. Bought a standard Savage bolt action 30-06 for testing. The examples noted here involved published loads of fast burning powder with cast boolits. Examples elsewhere involved reduced loads of slow burners like 4831 etc..

In my efforts to duplicate the effect (blow up a rifle), I'll need some specific loads to try based on actual results. Please don't suggest obvious unsafe loads (case full of Bulleye).

The 30-06 case should work well as it's large enough to allow the claimed "flash over" effect.

A controlled test should prove interesting.

[Larry Gibson]

Mr Humble

"Flash over" effect is an unproven theory and not the cause of S.E.E.

If your going to test for S.E.E. it might be helpful to you to go back to the other thread and read the article about the lab found causes of S.E.E. that are readily reproduced. You might pay particular attention to the use of low load density use of slow burning powders if you are going to attempt to reproduce an S.E.E. in your 30-06. Depending on the length and condition of your rifles throat you may want to use hard jacketed lighter weight bullets that can be easily pushed out of the case neck via the primer or hard jacketed heavy bullets with long bearing surfaces. Keep in mind also that given the expansion ratio of the 30-06 it is one of the more difficult cartridges to produce an S.E.E. in. A better prospect would have been a smaller caliber in a case with at least the capacity of the .308W.

Good luck and keep safe.

Larry Gibson

[Mr Humble]

In my reading I can find no contemporary data on SEE. Posters here state that they have seen the event occur. You may call it what you want but the outcome is the same. The theory is that either a primer or part of the powder charge causes the bullet to exit the case, lodge in the throat, then the balance of the powder ignites creating a huge pressure spike that dismembers the gun.

I would expect these observes to be able to provide data from their observed events rather than rely on decades old, foreign, unverified data using powder no longer made.

If you search the net there are many opinions of interest.

From African expedition blog: "Secondary Explosion Effect, or S.E.E. seems to occur when a "slow" powder is used and the powder charge reduced to below 15% of max. This will cause the powder to detonate rather that burn at the prescribed rate."

From CAS site: "powders ignite in one of two ways, conductive ignition and convective (or flash) ignition. Where conductive ignition is defined as most of the energy required to raise any grain of powder to its kindling point (temperature of ignition) is via low impedance paths offered by physical grain to grain contact. This is how one grain ignites the next grain of, eg, IMR 4831. This is an artifact of the heavy deterrent coatings, high internal thermal conductivity and large thermal mass and hence sink each grain represents.

Convective ignition is where no physical contact (and hence no conduction) is required, but where each grain is bathed in hot ambient gases (from the primer or from other grains burning), and due to its small thermal mass the entire grain is raised to its kindling point whereupon all its surfaces spontaneously ignite. This is how all the double base disc powders burn. Flash ignition is a special form of convective ignition, where the entire powder charge begins burning simultaneously."

From the mil-surp forum: "For more years than we have been around the have been reports of fire arms blowing up due to very light charges being used. The nay sayers always chime in with ‘it must have been a double charge of powder” “wrong powder used” or “the gun was faulty”
The truth is really a phenomenon of the powder not burning as it should. It detonated.
What this means is that a light or normal charge of powder that is 30% or less than the normal charge for a given load, detonated rather than burned in a controlled manner.
An SEE can happen when the charge is struck by the hot gases of the primer and blown forward against the base of the bullet. The moisture in the empty portion of the case condenses into steam almost instantly and cools the primers hot gases. The steam forms a buffer around the powder charge and the heat in the casing starts to rapidly degrade the powder grains. The powder “out-gasses” rather than burns and fills the case with extremely explosive powder fumes. These fumes are not burning powder gases, but rather powder degrading by the heat of the superheated steam and reverting back to its chemical composition of nitrated materials.
Many of today’s powders are of a double base of Nitrocellulose and Nitroglycerine. The rest are considered a single-base powder of Nitrocellulose. All of these powders are coated with a deterrent coating to control the speed of the burning powder charge. If this coating is damaged the powder will burn in an unregulated manner. It is no longer a propellant it is a source of extremely dangerous components.
These gases build up very quickly inside of the casing and compress to a fairly high pressure when their flash point is reaches and auto ignition occurs.
The burning gas is so volatile that as the gas ignites the velocity of the expanding particulates will exceeded 16,000 fps. There is no firearm made that can withstand these pressures. The casing will fail instantly and the high velocity pressure wave will shatter the firearm as it expands. "

M.D. Smith site: "The phenomena of Secondary Explosion Effect (SEE) is known to occur only with the slow powders at very low loading densities. Precious little is known about the mechanics of the phenomenon and it is not even known if the expression, Secondary Explosion Effect, is accurate. SEE, despite best efforts of the leading powder companies, cannot be reproduced in the lab, at least in the literature that I have been able to find. Some of the powder companies now are putting notations in their manuals not to reduce CERTAIN loads below 80% loading density. One should note that such notations are for a very limited number of powders and cartridges, such as W-W 296 in the .44 Magnum. Actual documented SEE cases were at densities much less than 80% and with slow powders.

Cast bullet shooters discovered SEE while experimenting with some of the very slow powders. However, they have been using moderate speed powders at much reduced loads since the days of Dr. Mann, with no untoward results. Only the very slow powders exhibit SEE."



I am willing to destroy a $300 rifle ..... it would be ironic if none of the believers were willing to facilitate the experiment, would it not ?

[rockrat]

Can't help you with data for a rifle, but my S&W 29 silhouette 44mag, is another story

[OS OK]

Isn't W-296 the one that was cautioned about using less than recommended charges?
I don't recall but I do think you have an interesting experiment though.

I would measure everything you can and even pour a chamber cast so you have empirical evidence of the different results should you not be able to blow her right off the bat.

Come to think of it...you might even be able to add to this post with 'mixed powders'...

Reloading With Mixed Powders ?

[Mr Humble]

If the original post is read, it did not involve handguns or 296 powder.

The subject was a M96 Swede, reduced loads of small rifle powder and cast boolits. Other events noted, involve reduced loads of slow burning powder.

Only an idiot would load mixed smokeless powders.

[Cap'n Morgan]

Good to see you're back, Larry.

[Larry Gibson]

Mr Humble

"Contemporary data" was posted for you in the other thread. That data (the Handloader) describes the produced S.E.E. event and the causes for it. All you're posting is the same old theories promulgated by individuals, not actual test results. Also "data" is available from ammo factory technicians who can readily produce an S.E.E. although they do not use that term as smokeless powder does not explode. Smokeless powder burns and the higher the psi the faster it burns. There is no "detonation" of the powder. Believe it or not but everything we read on the internet (seemingly your only source of information) is not true or does not actually happen.

Larry Gibson

[Mr Humble]

Larry, as I said before, the Handloader story has no attribution, was never repeated under controlled conditions, nor has any powder company removed a product from its list for this cause and the "powder technicians" you invoke do not exist.

If you cannot contribute anything beyond trying to start ANOTHER fight, I'll probably have to complain.

[tomme boy]

Call the # I posted. Hodgdon says they can make it happen on demand with a 243.

[Mr Humble]

Could you share the details with us ? There is nothing unique about the 243 soooooo what works with it, should work for anything. In looking at the Hodgdon site 243 loading data vs my 10 year old Hodgdon book, I don't see any loads dropped, warnings etc. Nor has Hodgdon abruptly dropped any powders suitable for the 243. Looking forward to the information you have from Hodgdon.

[BK7saum]

The 243 is more overbore than the 3006 and likely similar to the 6.5 Swede in expansion ratio of case volume to bore. Not necessarily unique, but not a 3006

[Mr Humble]

There is no such thing as an "overbore" cartridge IF the right powders are used. The term started in the 30s when Hi-Vel was the slowest powder. My Sedgley 22-06 is a perfect example. Made in the 30s, it could do nothing that an improved 219 Zipper could not. Fast forward to today and with H869 it's a 3700 fps with a 70 gr TSX. A 30-06 with a heavy bullet and the wrong powder can be just as much "overbore" as a 243.

If SEE exists. the right combination of bullet/powder will produce it.

And If it can be produced, the folks who make the powders and bullets that will produce it would be warning us of that possibility. They are not.

[BK7saum]

Overbore is overbore no matter what powder is used. It doesn't matter the powder you put in it. I am referring to a case volume to bore cross sectional area. Call it inefficient if you want to.

If overbore doesn't exist, then why not go to a 22 short for your experiment.

As far as warnings, Powder manufactures wouldn't and don't need the additional warnings if the current warnings are followed to not load less than 10% or 5% of max charge or drop below starting loads of recommended data in the manuals. No powder manufacture wants to say "Hey, our powder can blow up your firearm" if improperly loaded.

Can you point me to an alleged SEE event where load manual data was used?

[Der Gebirgsjager]

Here's an idea-- if you want to know something, ask. Why not use the telephone, call the various powder companies, and ask them about SEE?

Steve Hornady is well known for being willing to talk to his customers, and I've consulted with Lee on several occasions. If there is solid evidence for the SEE situation I'm sure they'll tell you what they know.

Afterall, are they likely to withhold information so that you can injure yourself and sue them?

[Black Beard]

Mr Lees manual says that a load from another manual caused very high pressures when the gun was fired downwards. I suspect it was one in an earlier edition of the Lyman cast bullet manual. They changed it for the current edition.I think SEE is caused by powders with special coatings getting swirled around in low density loads with partial ignition. The coatings on all the powder particles get burned off at once, without the pressure going up since the coatings won't make gas like nitrocellulose. Then all the powder (now without coatings) starts burning all at once and the bullet is still in the chamber. Pressures spike and it goes boom. This may not explain Mr Lee's story.That is my theory, with no proof or evidence. No one can prove it wrong. BB

[EDG]

I had 2 primers blown in a 1891 Mauser with Accurate 2495. At the time Accurate 2495 was a new powder and some of the data came in a flyer that was folded and stuffed into the cannister before it was sealed at the factory. There was no data for the 7.65 Mauser round so I interpolated and gave it a try. Out of the first 10 rounds I had 2 blown primers in one rifle. The second rifle I was shooting had no blown primers using the same loads. All the loads in this series sooted the entire exterior of the cases. I eventually tried higher charges in the rifle that did not blow the primers and they shot normally. Eventually both rifles wound up using charges about 4 grains higher than the loads that blew the primers. Sometime afterward Accurate listed data for the 7.65 Mauser on line and my top load fell right in the middle of their data.
If you want to observe an unexplained pressure excursion you can certainly get one easily enough with A2495. When contacted about this Accurate was so uninterested that I decided I would never buy their powders again. I still have about a pound of the 2 pounds that I originally bought.

[EDG]

Yes Winchester data used to state shoot the load exactly as listed.
As a newbie loader nearly 50 years ago I tried H110 as a reduced load powder in a 30-30. With the powder toward the bullet it shot normally and with the powder next to the primer the bolt locked up some. So I abandoned spherical powders for any reduced loads in rifles.

Isn't W-296 the one that was cautioned about using less than recommended charges?
I don't recall but I do think you have an interesting experiment though.

I would measure everything you can and even pour a chamber cast so you have empirical evidence of the different results should you not be able to blow her right off the bat.

Come to think of it...you might even be able to add to this post with 'mixed powders'...

Reloading With Mixed Powders ?

[OS OK]

There is no such thing as an "overbore" cartridge IF the right powders are used. The term started in the 30s when Hi-Vel was the slowest powder. My Sedgley 22-06 is a perfect example. Made in the 30s, it could do nothing that an improved 219 Zipper could not. Fast forward to today and with H869 it's a 3700 fps with a 70 gr TSX. A 30-06 with a heavy bullet and the wrong powder can be just as much "overbore" as a 243.

If SEE exists. the right combination of bullet/powder will produce it.

And If it can be produced, the folks who make the powders and bullets that will produce it would be warning us of that possibility. They are not.

Are you going to try to blow that rifle up or not? Are you going to chronograph and video, do you have any way to measure pressure?

[nekshot]

Mr. Humble, please stop creating a fuss with others until you have concrete evidence to back up your argument. You got the idea so go at it and record your process till it blows then come tell us. Till then I get really impatient with dribble talk and arguing. While you are punching the key board you could have a good bit of experimenting done that would be factual. I understand your desire to understand this but you have the goods to experiment so have at it!