Keeping bullets in the car in the summer heat

F

FUD

Moderator
Would it be a good idea to keep a box of ammo in the car in the summer in southern Florida or will the heat & humidity have adverse affects on the ammo (such as an explosion or other failures that would make the ammo no reliable)? I carry one spare magazine with me but with a MK9, that's only 13 rounds (carrying the larger 3913TSW still gives me only 15 rounds) and according to Mas, LEO who post perfect scores during qualification usually have a 20% hit rate in the real world. If trained LEO do so poorly, I suspect that I would do even worse and having some extra ammo around doesn't seem like a bad idea.
Share what you know, learn what you don't -- FUD
fud-nra.gif
 
Well, I really doubt that the rounds would cook off, even if the inside temp gets to 150F.
I wouldn't leave a loose round on the dash, and place my glasses in such a way that the suns rays would focus on the primer, though.
(Kinda like that ammo+microwave thread).

I honestly don't know about the humidity.
I would guess that it wouldn't be a problem, but am not sure.

Extra ammo is a good thing; but extra ammo in the box (rather than in magazines or speedloaders) won't help you much in a firefight.
$.02, -Kframe
 
The odds are slim to none that heat will set your ammo off (though the pressures may skyrocket!). Still, keep loaded mags, ammo boxes... out of direct sunlight.

I would be concerned with the long term effects of humidity on ammo. Guess the best advice would be to rotate "car" ammo like you do with your mags.
 
I keep an extra 50 rds in the glove compartment at all times.Now this is AZ where inside car temps can go 150 plus.So far no problems but I still rotate the rds.I normaly keep handloads so I just shoot up old stock and replenish with new.The only thing I have seen is with cast slugs it will melt some of the bullet lube and for some reason it will not feed in a colt but my sig eats it up.For you with the high humidity I would maybe buy some primer sealer and make sure the primers are sealed.If crimp is good I don't think you will have any problem around the slugs.

------------------
beemerb
We have a criminal jury system which is superior to any in the world;
and its efficiency is only marred by the difficulty of finding twelve men
every day who don't know anything and can't read.
-Mark Twain
 
Humidity shouldn't be that much of a problem inside the car. High in-car temperatures tend to dry out the air inside.

Chambers pressures can be higher, as bk40 pointed out. I'm guessing that would be less of an issue in most semi-autos, compared to, say, +P in a .38.

Degradation of the powder in loaded cartridges from heat and humidity typically takes years. I have some GI .45ACP from 1943 which still shoots just fine; some .243 from 1968, ditto.

Regards, Art
 
Having lived in Louisiana, Arizona, Alaska and now East Texas - I can give you an informed opinion - but an opinion, none the less.

Heat deterioriates ammo more than cold. Chambering a round that had been simmering at 120 to 150 in my car in an exposed parking lot in mid-July would lead me to expect higher chamber pressures than normal when cranked off. If you have a solid gun, by a reputable manufacturer, this should not be a problem - just don't make a habit of it - especially if you use +P ammo.

I would expect the long term effect on the powder of repeated over heating and cooling would be to deteriorate the powder and thus give you inconsistant chamber pressures. I would expect (within reason, say a span of seasons) that the ammo would still go "Bang" - but some of it would go BANG and some would just go bang - or maybe even bing.

Humidity? Based on my experience with snow machines, pickup trucks and small water craft - if it hasn't been submerged, a season or two won't hurt it. If it has been submerged - a lot of hours of drying will make it a "maybe" for reliability.

All of the above advice to rotate your ammo is probably very good. At least once a year and preferably once a season. Two years in your car? All of the ammo would probably still go "bang" - it's just that two consecutive rounds might not go quite to the same point of aim.

If you have a stiff suspension in your vehicle and drive on rough road regularly - and have loads which do not fill the case - then you may be subjecting your powder to a "tumbling" action. Still, a year shouldn't "greatly" effect it (unless you're very high milage) - but rotate, just to be sure.

Just my opinion. YMMV.


------------------
Jim Fox
 
All my ammo has special air conditioning units built in as well as on board guidance systems...
Don`t yours??? LOL :)

------------------
SHOOT,COMMUNICATE AND MOVE OUT !
 
Think about how hot the chamber of a pistol gets after several strings of rapid fire. Pretty darned hot, right? (I don't know how many degrees Centigrade, but I'm sure it's hotter than the interior of a parked car, even in Florida.) Yet a round still won't "cook off" (ignite from heat) under those circumstances. Therefore, I think it's very unlikely that ammo stored in a car would explode from the heat.

As others have pointed out, though, hot and humid conditions aren't good for long term storage. Just rotate your ammo every year or so and you should be fine.
 
After shooting in many carbine matches on nice June summer days in Pnoenix I have learned one thing. Stay away from Winchester 748 in .223s when the temperature is over 110! I've seen way too many case failures from this combination.
 
FWIW, I used to keep a loaded grendel p10 in a little cubby behind a tray in my dashboard. It was only in there for a little over ten months but when I took it out and fired it six of the ten rounds in the gun were useless. Thats here in Colorado where the temp is pretty moderate most of the time. I no longer store ammo in the car for more than about a month befor taking it out to the range and using it up.

------------------
Remember, Wherever you go, there you are.
 
I was thinking about that just today. I was on an out of town business trip and planned to stop by an outdoor range I pass by on my way home. I had a couple of guns in the car and a couple of hundred rounds of ammo. It was 91 degrees in the shade. It cooked in the mid-day sun for four hours while I was in a meeting.

Knowing the lay out of the place my meeting was, I parked my car so I had a visual line of site of it through the conference room window. I was a little worried about a thug getting their hands on my Kimber. After a while, I started to worry about whether that car was going to go up and if I'd selected the wrong seat in the conference room if it did.

Well, I'm home safe and sound. Oh, yeah, I stopped by the range and all 200 rounds fired perfectly. The best I can surmise is that prolonged exposure to heat causes rounds to shoot low and to the left--or maybe that was only me? :D

RJ

------------------
"Never turn your back on the crew."
 
Massad Ayoob did an article a few years ago on the effect of temperature on the ammunition. You will get increased chamber pressures. Though not dangerous, it is something to be aware of.
I live in SW Florida, and have been carrying a handgun in and around the car daily for 21 years. So far I haven't had one problem (that I've noticed) with any particular ammo due to heat and humidity.

If your going to carry extra ammo, get some magazines. If you need them, you'll "need" them.
BTW: LEO's aren't always the best shots around. And when the do have to shoot, it's always during times of HIGH stress.
 
Some ammo (because of the powder used) will be affected by storage in high heat; others will not.

Ask Frank James (still mad about his subgun).

I know because I test..........

------------------
"All my ammo is factory ammo"
 
It may not the best place for a gun and ammo but that small coleman lunch cooler in my back seat doesn't have pop or ice in it. Since the cooler doesn't have ice in it the inside temp still gets warm BUT I think the average temperature is much lower and stable. I use it in both summer and winter. No-one seems to give the cooler a 2 nd look unless of course they are thirsty.
When you transport ammo to a match in hot summer days, or any time in Texas, have you ever thought about transporting it in a cooler??
 
You must log in or register to reply here.
Back
Top