Found box 9mm in my trunk; hot summer; safe to shoot?

[NXMR]

Hi all,

I found a box of Win Super X 9mm in my trunk. Apparently it's been there all summer. I must have overlooked it after a day of shooting at the range - the last time I had my 9mm out shooting was late this spring.

Anyway it's been really really hot here in TN all summer long, and this ammo has been in my trunk for probably three and a half months.

Is it still safe to shoot it?

Thanks

[learningcurve]

I might be wrong but I think once it is sealed so to say it's ok. It's the extreme temp change from say hot hot hot to really really cold that is bad for it. That would be my understanding. Hopefully I am not to far off on this.

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[Sparks1957]

Ammo gets subjected to more extreme conditions than that and is still reliable, otherwise our troops in hot desert climates would be in deep trouble.

It's fine.

[JohnKSa]

It may have degraded a little, but my experiments with cars, ammunition and TX weather has not, so far, produced any noticeable problems.

I've fired ammunition that has spent a couple of years in a car that is parked out doors all year round and it has always worked perfectly.

[oneounceload]

I doubt it has as hot as it has been in the ME, and their ammo works just fine.........go shoot it

[NXMR]

Awesome!

Thanks y'all - will do

[mySig229]

Let's put it this way...Snipers in Afghanistan lay their rounds in the sun to make them hot. Better burn and velocity. If they're too hot to hold you may have trouble loading them without gloves though. Lol

[FrosSsT]

Snipers in Afghanistan lay their rounds in the sun to make them hot.

Yep. Higher burn rate - higher muzzle velocity. It can mean 10 inches high at 1000 yards.

[JohnKSa]

It can mean 10 inches high at 1000 yards.

I know this is a little off-topic, but I think it's worth mentioning that it can also mean unsafe pressures unless the ammo has been tested at the factory over a wide range of temperatures.

The big ammo makers with reputations for putting out high-quality ammunition do that kind of testing. Handloaders and some of the "boutique" ammo manufacturers may not. If you're going to be shooting ammunition while it's actually hot, as opposed to after it's been hot and cooled back down, be sure that it's good quality factory ammunition from a well-respected ammo company or that it's been otherwise tested to insure that it's safe to fire at relatively high temperatures.

[akguy1985]

i carried a box of .45GAP in my glovebox for a few months. It gets hotter than this in Iraq and our militaries ammo shoots just fine.

[BPowderkeg]

the ammo will be just fine to shoot.., just don't microwave it

trust me, i have heard of this happening, and it was NOT a child !!

[jmr40]

As long as the ammo has cooled down to a reasonable temperature it should be fine. Firing it when hot could create a dangerous overpressure situation.

Snipers in Afghanistan lay their rounds in the sun to make them hot.

Yep. Higher burn rate - higher muzzle velocity. It can mean 10 inches high at 1000 yards.

There MAY be some truth to this, but not for the reasons stated.

Some powders are very temperature sensitive and you could expect about 1 fps difference for each degree temperature changes. You could see 100 fps difference in rifles between ammo fired at zero degrees than when fired at 100 degrees. If you have a max pressure load that is perfectly safe at 70 degrees and leave it in a car it could easily reach 150 degrees and be unsafe to fire while it is at that temperature. Let it cool and it is again safe to fire.

Military specs call for powders that are very tolerant of extreme temperature ranges. There will be differences, but not nearly as much as some powders used in typical hunting loads. They are not heating up the ammo to get the ammo faster. Their trajectory calculations are based on the actual air temperature, among other things. Getting an extra 10" at 1000 yards is not a good thing if it messes up your calculations and causes a miss.

In the desert the night time temperatures can be very cold, with daytime temps very hot. Ammo stored in a shady area at night could be 50-60 degrees cooler than the actual air temperature. I could see setting ammo out to allow it to reach the same temperaure as the surrounding air so their trajectory calculations are accurate.

[FrosSsT]

There MAY be some truth to this, but not for the reasons stated

I never said it was a GOOD thing lol. Temperature changes the bullets trajectory at long distances. Hot - high Cold - low. Even humidity comes into play at such distances.