Car Temps

[LS-208]

During the summer months even with the windows cracked it can reach about 140+ degrees in your vehicle. I personally leave one of my semi-auto's in my truck all the time. Never thought much about the effect it might have on the pistol or even the ammo for that matter. Anybody have any knowledge in this subject?

 

[beardedjesse]

If you live in an area that is humid all the time you can potentially have problems with rust/corrosion, if you leave a round in the chamber. You also have to consider, aside from the heat, the possibility of someone breaking in to your car and taking your firearm. I usually don't do "A" w/ my gun if there is any doubt in my mind. I guess I'd rather be safe than sorry. Anyway, thats my two cents haha!

 

[SilentBob]

OP - good topic. Great reply from beardedjesse too. It's something to think about, especially living in an area that gets very hot and humid in the summers. We always hear "store in a cool, dry place" but we usually only think of this rule for our homes.

 

[Hoganbeg]

Higher ambient temperatures raise the internal pressure of the cartridge case when it fires. This is accounted for with factory ammo. If you roll your own you are in uncharted territory; especially with hotter-than-normal loads. P.S. No pun intended!

 

[NRA Lifer and Proud]

Once several years ago I left a box of factory ammo in my truck from January to my normal "Fall shoot-fest" with the guys. Every round went off with no issues. IMO quality rounds that have sealed case necks and primers "shoudn't" be effected too bad. I probably wouldn't do that for years but from the deep cold of a New England winter through the hot humid summer into fall had no effect that I could see. It is known that if a round is heated due to weather the powder burns faster and raises the pressure so point of impact will be raised as well. How much this would be noticeable in at handgun ranges versus rifle ranges would be an interesting experiment.

With that said, all the above points are valid as well. I wouldn't leave a loaded gun in my vehicle in an area that it might get stolen.

 

[cjs]

I doubt the temperatures would affect firearms or ammunition...a holster, on the other hand, might be an issue. I've heard of Kydex holsters and carriers getting a little deformed when left in the desert heat of a car.

 

[billwot]

Both of my carry guns have some type of rubber grips. I would worry more about the effect of high temps on the rubber grips than anything else.

 

[JSDinTexas]

Glock lists the maximum operating temperature for its pistols as 70°C (~158°F). That is not storing but operating, so we can assume the Glock will withstand more. In fact, the Glock receiver made from a polymer, called nylon 6 I believe, can withstand close to 400 degrees before crystallizing begins (polymers start by crystallizing - they melt later).
You can therefore also put it in the dishwasher running around 150 degrees hot water to clean it (disassembly is recommended but not necessary :sarcastic.
I would be more concerned about accessories such as night sights, telescopes, rail lights, and so on.

 

[LS-208]

Interesting

I am finding all this pretty informative. The first thought I had was that the chambered cartridge would swell and get stuck in the chute. I had no idea how hot the polymer could actually get before it begins to warp or deform. I also was thinking that the heat would weaken the magazine springs as well.

 

[Finalwarning]

As a reloader I can tell you that gunpowder, even if sealed, will deteriorate with exposure to excessive heat. It will still burn but not as evenly. This means that the velocities of the cartridges in a box will be a bit more varied. If you are looking at a box 1- 2 years old the difference will probably be within 50 fps. Longer will be a larger variance. Velocity impacts accuracy. I have shot cartridges with no special storage ( including being carried in a car part of the time ) that were 10 years old that still gave 3 1/2" groups at 25 yards on rest.

 

[NRA Lifer and Proud]

I would be more concerned about accessories such as night sights, telescopes, rail lights, and so on.

I worked for a Manufacturer of Tac lights lasers and I know ours were tested for temperature extremes both hot and cold. They needed to not only be able to function in the Arctic but in the hottest deserts as well. What couldn't stand up to either most of the time were the batteries. The actual storage temps were even colder or hotter than what they were designed to function at but once they returned to the operating range they were expected to function per the Mil-Spec.