Myth or fact? Vibrating live ammo is dangerous.

44hunter45

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Over the years I've read time and again about someone who "blew up their gun" and the only possible explanation was their ammo had bounced around on their pickup dashboard for decades.
What if their bore was obstructed and they did not know it, etc?

I can concede the concept that powder physical characteristics (and therefore burn rate) could be changed by enough time and agitation.

How much time?
How much agitation?
How much change in pressure?
Ball powder vs extruded powder.
What load density?

Theories and real world anecdotes, please.
 
The more likely explanation is the extreme temp changes.
120°F or better during the day(depending where you live). Then 50s at night.
Winter will have the cold temp (again, depending where you live).

I'd say if you repeat that cycle a few times, the chemistry of the powder will change.

Vibration, i don't believe will have anywhere near as much effect.
 
Idk but I recently ran 15 years worth (Couple hundreds rds) of misc “truck ammo” thru my pre accutrigger savage 110 06 and failed to blow myself up. Lol..

I have However been standing 2’ from a Benelli sbe 2 that never had anything but factory ammo ran thru it that exploded mid barrel like a pipe bomb. The gun and spent Winchester xpert#3 were sent to benelli who replaced it but never gave an explanation. Doubt it was from the shell being on the dash board tho. Maybe..
 
Not sure how much stock I would put in to claims that vibration has any effect on loaded ammunition, even ammo manufacturers often tumble completed rounds before packaging. Figure that would put more vibratory forces on ammunition than years rolling around in a bag or truck. I could see temperature having more of an effect (box sitting on dash in sweltering vehicle), powder breaking down over the years (guess it could vary by powder, or storage method as I've seen a lot of very old milsurp ammo used).
 
Myth. Even if it went off, its more like a firecracker than anything else.

now I could see a old round being a dud and not sending the projectile clear of the muzzle, the shooter not recognizing the situation and loading another round and firing which would most assuredly cause a kaboom.
 
Myth. Even if it went off, its more like a firecracker than anything else.
I'm not sure what you mean by this. You mean going off in the tumbler?

Not sure how much stock I would put in to claims that vibration has any effect on loaded ammunition, even ammo manufacturers often tumble completed rounds before packaging. Figure that would put more vibratory forces on ammunition than years rolling around in a bag or truck. I could see temperature having more of an effect (box sitting on dash in sweltering vehicle), powder breaking down over the years (guess it could vary by powder, or storage method as I've seen a lot of very old milsurp ammo used).

Thanks for playing.

The myth is real. I've seen it come up occasionally over the years.
It is however, not fact.

I have been tumbling my finished ammo for years to get the skin oil off. @JeffJ is correct. Why does factory ammo not have finger prints on it? Because they tumble it.

I had just read this "fact" about vibrating ammo being dangerous in some forgotten reloading magazine. (It was before the internet, so it must be true. ) I will never forget that it was on New Years Eve and I happened to have some 30-06 in my tumbler in the basement to run overnight. We were awakened by a loud BOOM just after midnight and I jumped up saying, "My God, it's happened." and ran to the basement to check my tumble, which was happily vibrating away. Then another BOOM. It was at that point I remembered that is was New Years. Coming back up the Mrs45 wondered if I had lost my mind and I explained it all to her. To this day she will look at me random times and say, "My God, it's happened!"


Out
 
@44hunter45 Yes, even if it went off in the tumbler, it would be as powerful as a firecracker, not much damage done
Yup. As crazy kids. My buddy and I used to cook off rifle rounds in our camp fire. You find the case opened up like flower petals. The most dangerous thing is brass shrapnel. Not really any louder than just a primer.
 
Over the years I've read time and again about someone who "blew up their gun" and the only possible explanation was their ammo had bounced around on their pickup dashboard for decades.
What if their bore was obstructed and they did not know it, etc?

I can concede the concept that powder physical characteristics (and therefore burn rate) could be changed by enough time and agitation.

How much time?
How much agitation?
How much change in pressure?
Ball powder vs extruded powder.
What load density?

Theories and real world anecdotes, please.

For what it's worth (Ammo and Explosives specialist with the Canadian Military), here's my humble opinion on this. This is MY opinion and it is based on well over a decade in my field as well as conducting investigations on accidents and incidents involving all sorts of munitions, EOD, etc.

Small Arms Ammunition is extremely "stable" in comparison with other munitions. In terms of vibrations/agitations, you would require extensive exposure over the course of months if not years to see any difference. The most issues I have seen with this are in large caliber munitions (20mm+) where extensive vibrations mixed with loading and unloading of weapon systems created extensive wear on the cartridges and projectile/case separation was the main issue. With large caliber ammo, you have the possibility of stoppages or worse, possible spilling of propellant inside the weapon system which can ignite.

Now with changing the physical characteristics of the propellant which in turn would alter (accelerate) the burn rate so badly that it would be apparent or worse, lead to a catastrophic event, I have NEVER witnessed or heard of such occurrences in small to medium caliber ammo. Large caliber, rocket motors, etc, 100%. This is especially a problem in the rocket motors of rockets or missiles. Cracks in propellant sticks or rocket motors create voids which in turn can lead to the deflagration or detonation of the explosives. Same thing can occur in high explosives warheads, cracks, bubbles or air pockets in the filling are extremely dangerous and can lead to the warhead detonating inside the weapon system upon setback force being applied to the warhead/projectile.

Now, the rattling and vibration of small arms ammo can lead to the ignition of the cartridge, but for external forces being applied to the percussion primer (or static to an electrical primer). This happens a lot, especially when troops throw belts of small arms ammo or larger caliber on hard surfaces (or soft with hard objects which can be other cartridges), and the primer strikes something hard. This doesn't really pose a threat in small caliber ammo since the deflagration of a single cartridge is usually contained to the single cartridge and the fragmentation is minimum. That being said, it is extremely dangerous in large cal ammo such as 25mm+ where the deflagration of the cartridge can take out your hand or leave you blind.

Cook-offs; these are real occurrences and can happen somewhat easily in the weapon system or outside. For example, a machine gunner is shooting at rapid rate with a .50 cal. He shoots an entire belt, loads a second and begins shooting. He gets a stoppage two+ belts in, clears the weapon and a live cartridge is ejected down in the hot pile of brass, seconds later, the gunner gets his ball sack peppered with hot brass fragments. Also, same scenario, a gunner has been firing hundreds of rounds without doing a barrel swap, he thinks its funny that the barrel is turning red, stops shooting and all of a sudden a cartridge in the weapon deflagrates, or even worse, it deflagrates when he opens the weapon's cover.

These a just a handful of scenarios but I have either witnessed or investigated several other more. From experience, 9/10 the user or weapon system is to blame.
 
For what it's worth (Ammo and Explosives specialist with the Canadian Military), here's my humble opinion on this. This is MY opinion and it is based on well over a decade in my field as well as conducting investigations on accidents and incidents involving all sorts of munitions, EOD, etc.

Small Arms Ammunition is extremely "stable" in comparison with other munitions. In terms of vibrations/agitations, you would require extensive exposure over the course of months if not years to see any difference. The most issues I have seen with this are in large caliber munitions (20mm+) where extensive vibrations mixed with loading and unloading of weapon systems created extensive wear on the cartridges and projectile/case separation was the main issue. With large caliber ammo, you have the possibility of stoppages or worse, possible spilling of propellant inside the weapon system which can ignite.

Now with changing the physical characteristics of the propellant which in turn would alter (accelerate) the burn rate so badly that it would be apparent or worse, lead to a catastrophic event, I have NEVER witnessed or heard of such occurrences in small to medium caliber ammo. Large caliber, rocket motors, etc, 100%. This is especially a problem in the rocket motors of rockets or missiles. Cracks in propellant sticks or rocket motors create voids which in turn can lead to the deflagration or detonation of the explosives. Same thing can occur in high explosives warheads, cracks, bubbles or air pockets in the filling are extremely dangerous and can lead to the warhead detonating inside the weapon system upon setback force being applied to the warhead/projectile.

Now, the rattling and vibration of small arms ammo can lead to the ignition of the cartridge, but for external forces being applied to the percussion primer (or static to an electrical primer). This happens a lot, especially when troops throw belts of small arms ammo or larger caliber on hard surfaces (or soft with hard objects which can be other cartridges), and the primer strikes something hard. This doesn't really pose a threat in small caliber ammo since the deflagration of a single cartridge is usually contained to the single cartridge and the fragmentation is minimum. That being said, it is extremely dangerous in large cal ammo such as 25mm+ where the deflagration of the cartridge can take out your hand or leave you blind.

Cook-offs; these are real occurrences and can happen somewhat easily in the weapon system or outside. For example, a machine gunner is shooting at rapid rate with a .50 cal. He shoots an entire belt, loads a second and begins shooting. He gets a stoppage two+ belts in, clears the weapon and a live cartridge is ejected down in the hot pile of brass, seconds later, the gunner gets his ball sack peppered with hot brass fragments. Also, same scenario, a gunner has been firing hundreds of rounds without doing a barrel swap, he thinks its funny that the barrel is turning red, stops shooting and all of a sudden a cartridge in the weapon deflagrates, or even worse, it deflagrates when he opens the weapon's cover.

These a just a handful of scenarios but I have either witnessed or investigated several other more. From experience, 9/10 the user or weapon system is to blame.
Great Reply!! Its worth a lot.

When I was about 14 my then B.I.L. bent a 45 Colt round closing it in his TC Contender. He pulled it out and tossed it and it exploded about 30 feet away. Up to that point I had assumed that a round would always land bullet first.
 
If ammo was to explode dew to the vibrating of a truck ride on bumpy roads it would not be safe to be on the Custer in November.
 
I heard a story a long time ago where a guy found a box of .243 win that had been riding around under the seat in an old ranch pickup (for many years). Naturally he went to fire a round and blew up his rifle. The consensus of the story was that the powder pellets had turned to "dust". I don't know if it's true, but it seems possible to me.
 
I don't know how much of these things are true but something Ive found over the years is that if I don't load a lot more ammo than I need, I never have a problem with it. If I don't leave ammo sitting out in bad places, again never a problem. If I feel I need to tumble twice, I don't, I'd do it before sizing and right after. Never a problem with tumbling loaded ammo as I simply don't do it. I find no reason to go looking for trouble in uncharted areas!
 
First off if the ammo was loaded to be a lightly compressed load, the kernels/grains wouldn't be able to move inside the case. Secondly the fact that IMR offers some powders as SSC super short cut versions somewhat nullifies that explanation. I suppose it's possible that an underloaded powder charge could pulverize over time.
 
Vibratory tumblers have the potential to erode the coating that may or may not be used for that specific powder to control burn rate.

Ammunition manufacturers do briefly put their finished loaded rounds in a rotary (not vibratory) tumbler for a final polish. I have no idea how long is long enough to polish but not compromise the powder.
 
The former gunwriter Bob Milek [now deceased] used to talk/write about tumbling his handloads. His disclaimer was that "I am not saying what you should do, I am saying what I do." I doubt that tumbling for a few minutes to clean your finished product is any big deal. I usually wipe my cases after sizing to remove any wax/lube.
 
The former gunwriter Bob Milek [now deceased] used to talk/write about tumbling his handloads. His disclaimer was that "I am not saying what you should do, I am saying what I do." I doubt that tumbling for a few minutes to clean your finished product is any big deal. I usually wipe my cases after sizing to remove any wax/lube.
I sure miss his writings. First gun writer I read.
 

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