Can Ammo Sit In A Hot Car Without It Going Off?

Having firearms and ammo in a hot car is a concern for many gun owners. This article discusses myths about ammunition igniting due to heat and provides essential tips for safely storing firearms in your car during the summer.

As summer heats up, questions about the safety of keeping ammo in a hot car during the summer have become more common. Many concerns center around whether ammunition might self-ignite or if a round could discharge due to high temperatures. This article aims to dispel myths, provide accurate information, and offer practical tips for safely storing firearms in your vehicle during summer.

Myth Busting: Ammo in a Hot Car

Firstly, it is essential to debunk a prevalent myth: a car’s interior temperature will not reach the level necessary for ammunition to “cook off.” Cooking off refers to the primer in a round igniting due to ambient heat.

If a round of ammunition is thrown into a fire (which is never recommended), it can cook off because the fire’s heat exceeds the temperatures required for the gunpowder to explode or the primer to ignite. Modern ammunition consists of several components:

• Smokeless primer: Incorporates nitrocellulose.
• Lead projectile.
• Gunpowder.

For context:

• Lead melts at 621 °F.
• Nitrocellulose ignites at around 320-338 °F.
• Gunpowder ignites at 801-867 °F.

Even on the hottest days, such as the record 134 °F in Death Valley, California, on July 10th, 1913, the temperature is far below the levels required to ignite these components.

Vehicle Heat and Its Effects

Inside a vehicle, however, the greenhouse effect can cause temperatures to rise significantly. When windows are closed and the sun is beating down, the trapped air absorbs solar radiation, potentially causing the interior to reach upwards of 212 °F, where water boils. However, this is still not enough to ignite ammunition primers.

Safe Storage Practices for Firearms in Vehicles

While it is unlikely for ammunition to cook off inside a vehicle, there are best practices to follow when storing firearms in vehicles during hot weather:

• Use a vehicle gun safe: This provides an extra layer of security and reduces the risk of theft.
• Crack the windows: Allowing air to circulate can lower the internal temperature.
• Store in the trunk or a shaded area: Keeping firearms out of direct sunlight can prevent overheating.
• Limit storage time: Avoid leaving firearms in the vehicle for extended periods.

Even with this information, it is never recommended to keep a firearm or ammunition inside a vehicle that you are not in. There are of course times when you’ll need to leave your firearm behind, but do this sparingly.

Risks of Leaving Firearms in Vehicles

Beyond the concern of heat, leaving firearms in vehicles presents other risks, including theft and unauthorized access. Storing a firearm in a vehicle, even temporarily, should be done with caution. Ensuring that the firearm is secure and out of sight is crucial.

Firearm Safety and Responsible Ownership

Responsible firearm ownership extends beyond safe storage. It includes being aware of the local laws regarding firearm storage in vehicles. Different states have varying regulations, some requiring firearms to be unloaded and stored in a locked container separate from ammunition. Familiarize yourself with these laws to ensure compliance and avoid legal issues.

Military and Ammunition Durability

Modern ammunition is designed to withstand significant punishment without discharging. This durability is why military forces can navigate harsh environments without worrying about munitions spontaneously firing. However, for civilian use, it is still best to exercise caution and follow recommended storage practices.

Conclusion

While the risk of ammunition cooking off in a hot vehicle is exceptionally minimal, it is essential to follow best practices for storing firearms in vehicles, especially during the summer. Ensuring the firearm is secure, out of direct sunlight, and understanding local laws are critical components of responsible gun ownership and safe storage.

Safety Tip: Always store firearms securely in a locked container, use a vehicle gun safe when necessary, and be aware of local laws regarding firearm storage.