bad vibrations

[jakeswensonmt]

Someone on another thread posted a link to the rec.guns FAQ, which I had never read before, and I read the following in this article in the "MAKING YOUR SEMI-AUTOMATIC RELIABLE" section.

Rounds that have been stored in a car should be demoted after a few months, because cars get hot sitting in parking lots (and heat speeds up chemical degradation of ammo) and because vibration can cause the powder grains to rub against each other and grind themselves down, which in extreme cases has even resulted in guns blowing up when the ammo was fired.

Is there any truth to this vibration issue? The content of this FAQ seems to vary in quality, for example the author of one of the SIG vs. Glock articles has "owned my Sig for over a year and rented Glocks on two occasions" so I'm taking it all with a grain of salt.

 

[SilentHitz]

so I'm taking it all with a grain of salt.

As do I. Do you know how many cases of ammo was bounced around in hot trucks, jeep, ect. every war since motorized vehicles have been around?

I'm 54, live in the hot humid south, and have never heard of such a thing happening. Then again, I've never been dumb enough to leave ammo in a hot vehicle all summer. I don't put much stock in his theory.

 

[Waitone]

Does the Army have SOP's in Iraq for air conditioning ammo storage?

I ain't buyin'

 

[DPris]

Some powders use a coating on the granules to control burn rate and flash emisions, among other things.

It is POSSIBLE (note the word POSSIBLE does not equate with WILL HAPPEN) that CONTINUOUS vibration COULD remove much of that coating & leave it as a smaller free-floating powder intermixed with the larger gunpowder grains, although the smaller powder grains could tend to "re-coat" the larger powder grains in a confined "mixing" space, depending on the ingredients of both. Such an occurance COULD affect the burn rate, POSSIBLY accelerating it & POSSIBLY increasing pressures.

EXTREME & PROLONGED vibrations that "grind" powder granules together COULD also reduce the size of individual gunpowder granules, and COULD affect the burn rate & pressures, too.
This would take a bunch of vibration over a period of time, and isn't likely to happen with even a fair amount of the type of vibrations inherent in auto travels over a "few months" in average urban settings or even country roads.

I'd be much more concerned over heat exposure. That does have a proven affect on powder deterioration. Such deterioration typically results in lower pressures on burning, though, not higher.
That's why I don't leave a gun in the car.

Denis

 

[DWARREN123]

Some folks even tumble their ammo after reloading to make it shine more evenly. I would not keep the same ammo forever, it is good to rotate it out by shooting but I don't think the vibration from being in a modern vehicle will hurt it. The heat would possibly do more to degrade the ammo than vibration.