Trapshooters Forum banner

1 - 20 of 56 Posts

·
Banned
Joined
·
3,913 Posts
Discussion Starter #1
shot and powder, no wad - detonation?

I'm not totally convinced there is such a thing as powder detonation with shotgun shells. But I'm not totally convinced there is never such a thing either.

So I am wondering if the conditions for powder detonation in a shotgun shell could be present if there was powder and shot, but no wad.

It's hard to imagine that such a shell would crimp in a manner that held the shot, but I have seen nicely crimped 410s that had nothing in them, no powder, no shot, no wad. It would also seem that a shell so load would emit a pretty audible shot rattle. But if it was so loaded, and adequately crimped, and the shot rattle went unnoticed, would the conditions be ripe for a powder detonation?

I'll add that a young man I heard a PhD Chemist/executive/trapshooter for a powder company once state a very dangerous situation could develop if powder and shot were mixed. He felt that combination would produce a semi-molten slug that could block the barrel or chamber. That's all I heard. I was young and wasn't about to question a person in his position.
 

·
Premium Member
Joined
·
12,319 Posts
I make two comments.

First, with no wad the shell would be so empty that the crimp would be close to non-existent, or even introverted. I do not think there would be enough 'back pressure' for any dangerous reaction to occur. Remember Big Bang Cannon of our younger years. The first of these were made of glass/pyrex to prove this very point - an explosion (the cannon did in fact have acetylene gas explode inside them) that has non-containment will cause little damage - just makes a loud noise.

Second, I do not believe there is not enough energy stored in the powder to to cause a molten state in the lead charge - you'd need to raise the whole mass to over 600 degrees F.
 

·
Registered
Joined
·
4,156 Posts
I once asked Ben at Alliant Powder if I had to worry about "detonation" if I reduced powder charges below those listed as starting loads. I was told there was no such thing as detonation in a shotshell (with SMOKLESS powders) even as you went down low enough that the wad and shot dribbled out the end of the muzzle.
 

·
Banned
Joined
·
3,913 Posts
Discussion Starter #4
HSLDS - I can't say I disagree with you. But my understanding of a detonation is that it is fundamentally a different phenomenon from normal shotgun ammo functioning. With a normal shotgun firing a solid (gunpowder) rapidly converts to a gas with associated heat and sound. It is the rapid expansion of that gas, the gas bubble, that pushes the wad and powder out of the barrel.

But my understanding of a detonation is that the reaction is so fast that shock waves are driven directly thru the barrel and receiver.

As far as the semi-molten slug, the key letters are SEMI. I'm not referring to something so molten it could be poured as you would pour lead into a bullet mold, but some elastic mass that would block the barrel or chamber. I'm sure there is some term for a metal in that state of matter, but my knowledge of metallurgy is insufficient to provide with that term.
 

·
Registered
Joined
·
2,021 Posts
With no wad, the powder burn would be exceptionally poor, akin to some poured on the open ground and ignited. The lead shot would play no role since the duration of the powder burn would not be long enough to raise the lead temperature to the point the lead melts. Any pellets stuck together would be because of residual powder ash. And, as noted, the shell would probably not have any sort of crimp to speak of. The .410, because of its significantly smaller radius, is about the only one you can get a crimp to form on an incompletely filled shell without taking special pains.
 

·
Registered
Joined
·
11,024 Posts
Nobody knows when it will occur and nobody knows why. But if it does occur your gun will be destroyed. HMB
 

·
Registered
Joined
·
1,737 Posts
So, if it is pellets, or a semi-solis, or a solid, what difference would it make? Why would it be different than a slug? And less powder could create a detonation? How would less powder create a faster pressure wave. Physics says no.
 

·
Registered
Joined
·
1,988 Posts
I won't speak to detonation of powder, but I can speak to the detonation in an engine and the above explanation is wrong.Detonation in an engine is the simultaneous combustion of the END gases in a chamber. The unburned charge is compressed (in an expanding VOLUME as the piston moves away from TDC) by the burning fuel, until the pressure in the chamber exceeds fuel ability to avoid combustion.
Preignition happens with a rising piston and is a non-spark induced starting of the flame front.
But detonation is an end gas, simultaneous combustion.

I'm not sure how detonation is induced with smokeless powder.
 

·
Registered
Joined
·
11,024 Posts
Normally smokeless powder when ignited by the primer under goes a controlled burn. When it detonates there is no controlled burn, the entire charge of powder releases all its energy at once. The resulting explosion produces a shock wave which is very destructive. HMB
 

·
Premium Member
Joined
·
12,319 Posts
I suspect that the shell would not crimp correctly (either too open or introverted) (double powder), or it would weigh too much in the hand (double shot) and you would notice.

Beyond that not much...

With no wad the powder and shot would intermingle and I suspect that would impede ignition. With nothing to impede the burning gases (there would be no wad to create a gas seal) you might get a burp of shot and unburned powder coming out the barrel.
 

·
Registered
Joined
·
21,600 Posts
I'm still looking for proof of hmb's magic occurrence. How is the experts are unable to reproduce this phenomenon in controlled labs but they can reconstruct a bomb from tiny pieces or even minuscule trace evidence? I know why.
 

·
Registered
Joined
·
11,024 Posts
Balderdash. The experts reproduce this phenomenon. If you doubt that, you can watch the video on Bing. HMB
 

·
Premium Member
Joined
·
12,319 Posts
grntitan,

No one has been able to reproduce detonation yet, so the jury is still out - it allows for claims of 'magic' or 'alien influence' but hey, what do I know.

Best engineering guess to date is this (It is seen in metallic cartridges - I know of no case actually attributing it to shotgun shells).

In a high volume shell with a powder charge of relatively small volume it is possible for the primer flash hole to be exposed at time of ignition. In a shell which is more full the primer flash enters a column of powder and the flame front will burn upwards (i.e., towards the bullet). When the flash hole is exposed there is a large surface area of powder which the primer flash can ignite all at once.

Here is born the theory of detonation.

It involves two things - a relatively large surface area of powder, and a source of 'back pressure' to contain the shock wave (at least initially) as it builds.

Two problems for shotgun shells here: First, it is REALLY hard to create a shotgun shell with a void over the powder for the primer flash to ignite - that pesky wad kind of fills everything up. Two, if there is no wad the powder and shot will mingle, the crimp will be poor at best and thus there will be no real source of back pressure.

Food for thought.
 

·
Registered
Joined
·
21,600 Posts
hmb,

Where is the video of shot shell detonation? How is everyone here can provide a link to their source of info but you never can? Simple copy and paste. Let's see it. I'm open to be priced wrong. It's happened many times before and I'm sure it will happen many times again. I've asked you umpteen times on here to show me proof and you keep telling me to search. You know where it is, please provide it for us.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~

HSLDS,

Trust me, my thoughts are riding in line with yours. I would love to see valid proof of a shot shell detonation.
 

·
Registered
Joined
·
2,987 Posts
"shot and powder, no wad - detonation?" I doubt it, probably more like a blooper.

FWIW my understanding of the phenomenon of destructive pressure in reduced rifle loads is caused when a relatively fast burning rifle powder (like 4198 for example) is loaded down to the point where the available space in the case is only half used or less. Let's say 20 grains or less behind a 300 grain bullet in a .45-70 case, if the rifle is fired from horizontal with the powder all laying evenly along the bottom of the case and not covering the flash hole instead of the charge burning from the back progressively to the front the primer flame can ignite the whole top surface of the powder charge at once causing a much higher than expected pressure.
 
1 - 20 of 56 Posts
Top