I have been asked to look for documentation, you know, the scientific kind as opposed to anecdotes, about what is generally termed the Secondary Explosion Effect. I have seen references to names like Howell, Brownell, K.D. Meyer and P.T. Kekkonen, but I have never been able to locate articles or manuscripts on the subject.

Can anyone provide any leads on this?

Good luck, and if you do find something with substance, please let us know.

I have heard all sorts of descriptions of it - mainly due to using low charges of slow burning powder.

Why would anyone do that I have no idea.

Someone said to get reduced velocity.

For reduced velocities we use small amounts of fast burning powders.

I saw a thread on 24 Hour Campfire (that's how I got the names I cited) with some loose translations of sections of a K.D. Meyer report, which is in German. He was the head of the DEVA Institute. But I can't find anything in any language which gets me any further down the road.

https://www.24hourcampfire.com...n/175869/type/thread

Guys used to load down cartridges like 300 Win Mags, way back in the 50s; there was no internet, no inexpensive and user friendly chronographs and pressure testing equipment, and internal ballistic data and information was often not based on facts, but wishful thinking. It is not useful to try to apply 21st century standards and knowledge that is readily available, to people in the middle of the 20th century who had no guidance other than what was in reloading manuals and magazine articles. Look at some of the claims for wildcat velocities and you will see. Guys flew by the seats of their pants and had a lot of fun. And slow burning was very cheap, much of it being WW2 surplus 50 cal and 20mm powder sold in paper bags. So, why not just reduce a load of slow powder for practice shooting; what can happen? Problem is, 99.9 percent of the time, nothing untoward happens, but when it does, it can be bad. Which is why it can't be scientifically replicated; it is a phenomena caused by demons and sorcery. Or something else; not proven and never will be. No reason to spend valuable time and bullets trying to make something happen that you can easily avoid anyway.

The person asking me has been called to testify in court about a "kaboum" situation in which a gun blew up (I don't know if there was personal injury) so the object is not to give reloading advice to anyone. The object is to find out what scientific literature, if any, exists on the phenomenon.

It seems the authors mentioned in my OP have written knowledgeably on the subject, even if there is no definitive explanation, only theory.

SEE is more correctly referred to as secondary deflagration explosion.
Where you have a solid particulate combustable material dispersed in air and ignition occurs.
The density of dispersion of the particulate matter is important in that if the density is at a critical level a very fast progressive burn off of the particles occur producing a explosion ( not to be confused with a detonation)

The burn off of a a load energetic propellant is limited by two factors Conduction and Convection conduction being the speed of burn off layer by layer of each particle and convection being the speed with which the burn is propagated between particles. The former largely remains constant in our typical propellants used , it is the latter that becomes critical. So load density.


The Babine Lake Forestry products explosion of 2012 near Burns Lake in BC an example of this effect. This explosion killed 20 mill workers.


Whether this actually occurs in our gun systems ( ie small arms) is debatable.

You might consider contacting Hodgdon Powder Co. 6231 Robinson, Shawnee Mission, KS 66202, 913-362-9455 and inquire about reduced loads of H110 propellant. There is a warning about reduced loads of this powder for the very reason you are asking about. I don't know how tight lipped they will be but it might be worth reaching out to them. I think if any entity is in the know on this subject they should be. Good luck

quote:

Originally posted by Luckyducker:
You might consider contacting Hodgdon Powder Co. 6231 Robinson, Shawnee Mission, KS 66202, 913-362-9455 and inquire about reduced loads of H110 propellant. There is a warning about reduced loads of this powder for the very reason you are asking about. I don't know how tight lipped they will be but it might be worth reaching out to them. I think if any entity is in the know on this subject they should be. Good luck

I will try to follow up on this. I have also advised the person to contact the French propellent makers as well as the proof house in Saint-Etienne. They might have something in French if he is lucky.

Let us know if you find anything.

quote:

Originally posted by Wink:
The person asking me has been called to testify in court about a "kaboum" situation in which a gun blew up (I don't know if there was personal injury) so the object is not to give reloading advice to anyone. The object is to find out what scientific literature, if any, exists on the phenomenon.

It seems the authors mentioned in my OP have written knowledgeably on the subject, even if there is no definitive explanation, only theory.

A gun blowing up can be caused by many different things.

Every single one that I have had seen was due to operator stupidity..

Yeah, but there are already hundreds of volumes on human stupidity.

quote:

Secondary Explosion

Search here, you may get lucky. https://search.usa.gov/search/...=5191&query=&commit=

quote:

Originally posted by Wink:
Yeah, but there are already hundreds of volumes on human stupidity.

When it comes to human stupidity, new inventors are born every day!

DDT:
Deflagration to detonation transition:
Condition where a low explosive (porous propellant) burns and the burn rate transitions to a supersonic rate.


This possibility of this phenomenon a major driver in the Hazard classification process of propellants in all countries that allow the sale and manufacture of powders and propellants including the USA. This determines how powders are sold and stored , it regulates how powder is made stored and distributed.

it is not necessarily a low density load that can do this ! Brownell who wrote a knuckle rapping letter in Handloader magazine against the editor Sept / Oct 1967 warning against propagating false information regarding the process and event they termed SEE

DDT has been implicated in various major accidents across the world in recent times.

Lapua Finland 1976: 22 cal bolt pistol cartridge powder ignited causing a DDT where about 700 kg of this powder went from a burn off to a detonation
French National Gunpowder Factory, Poilt-de-Buis, in 1975 a DDT where 12 tons of sporting rifle propellent went from a deflagration to a detonation exploding with the equivalence of 7 tonnes of TNT
Muiden Chemie B.V. propellant factory near Amsterdam in 1972. DDT during packing of propellant into containers. The igniter believed to be static electricity
Swiss Federal Propellant Plant at Wimmis in December 1978 100 tonnes porous propellant burned without going on to a DDT
USA 1944
Alabama Ordnance Works Fire
And in the same year the Louisville Fire
Both accidents were examples of DDT
Testing for hazard for DDT includes small vessel testing which would fit with the size of a single cartridge case

just to add
there has been a huge interest by defence explosives experts in the use of ordinary reloading propellants in IED's used by terror groups domestic and foreign. Most if not all of domestic terror devices used and found contained over the counter propellants

As such a huge amount of research has been done and published on the potential of ordinary reloading powder detonating vs simply burning at a high rate.

I recall reading an article, I think it was by P.O. Ackley. He was discussing the theoretical causes of the effect. It seems that he tried several times in a controlled setting to cause one, but was unable to get it to "work".

quote:

Guys used to load down cartridges like 300 Win Mags, way back in the 50s; there was no internet, no inexpensive and user friendly chronographs and pressure testing equipment, and internal ballistic data and information was often not based on facts, but wishful thinking. It is not useful to try to apply 21st century standards and knowledge that is readily available, to people in the middle of the 20th century who had no guidance other than what was in reloading manuals and magazine articles. Look at some of the claims for wildcat velocities and you will see. Guys flew by the seats of their pants and had a lot of fun. And slow burning was very cheap, much of it being WW2 surplus 50 cal and 20mm powder sold in paper bags. So, why not just reduce a load of slow powder for practice shooting; what can happen? Problem is, 99.9 percent of the time, nothing untoward happens, but when it does, it can be bad. Which is why it can't be scientifically replicated; it is a phenomena caused by demons and sorcery. Or something else; not proven and never will be. No reason to spend valuable time and bullets trying to make something happen that you can easily avoid anyway.

I like that.

Like the guy that went to his Doctor and rolled himself up, on the floor, into a ball with his left arm stuck half up behind his back and his right arm stuck half way down behind it and his two legs crossed at both knees and ankles.

"Doctor every time I do this, it hurts."

"Well then Mr Smith don't do it."

And https://thefiringline.com/foru...=4928827#post4928827

These guys got lucky.https://thefiringline.com/foru...wthread.php?t=535493

The firing of the primer moves the bullet into the bore, acting like a plugged bore. This causes a secondary pressure spike. The pressure can be high.
Government tests show primers alone , pushing bullets into the rifling. More so when the case in near 100 % full of slow burn rate powder. Ball powder is hard to get burning, even with a mag primer. The powder column moves the bullet, before the powder has started burning fully.

The descriptions by ALF are excellent and good descriptions of causes.

The effect is described in the documentation for QuickLoad where the author shows pressure traces that indicate pressures from the secondary "explosion" can be greater than the nominal pressure for the cartridge.

Having acknowledged the QuickLoad user manual description, I do not accept that the phenomenon is real, and if real that the pressures are anywhere near the max breach pressure.

The QuickLoad evidence can be as easily explained by electrical interference with the leads. The timing suggests that the rapidly moving plasma in the exhaust gases occasional transmits a small electromagnetic pulse that gets recorded.

certain smokeless powders with a high-nitroglycerine concentration can be induced to detonate

archives.fbi.gov/archives/abou...rd.htm#disablemobile

Propellants by Law are classified according to their Danger potential. Various countries use different classification systems but all basically come down to the same thing.

The ability to explode or in essence a potential to be used as bombs. It determines conditions of sale and storage

The main characteristic is the velocity of deflagration (burn)

Or propellants Single or Double are classically seen as Low order explosives ie having low velocities of deflagration ( burning ) at velocities lower than the speed of sound roughly 2000 m/s , when ignited by a flame ( Primer )

The same however may change 10 fold when ignited by means of booster initiation ie use of commercial detonators.... so a propellant which has a maximum Velocity of burn of 600 m/s can be boosted to 6000 m/s by means of a detonator. This applies to both single base and double base propellants.

a 2 pound canister of Bullseye ( double based ) is burn dangerous only when ignited by a match or a primer however stick a detonator in the same can and you have a bomb !

The burn process is a slow process, the transfer of heat from one zone to another in the propellant is the limiting factor. Chemically it limits itself

If however the propellant is contained so that pressure generated is contained , and other critical parameters like critical web size, load density etc are met then the pressure generated my induce a sustained shock wave that takes the propellant from a burn to a detonation.

Detonations are not burn offs but rely on chemical decomposition by means of a shock wave propagation through the propellant medium . Detonations can be initiated by a fast burn or initiation by a shock wave.

So as packaged our powders used are
Fire dangerous" only as to "Mass fire dangerous" as the classification goes up we get top a situation of "Burn to detonation" dangerous.

Every jurisdiction tests propellants to a standard in terms of its danger to misuse ! It applies to the US , UN and European countries like Germany , Sweden, France the Netherlands and England.