Gun safes are typically not airtight, but that doesn't mean they're not secure. The main purpose of a gun safe is to provide protection against fire, theft, and unauthorized entry into your home. If you store valuables or documents in the same space as your guns in an airtight container such as a vault, then you may want to get a different type of storage unit because it's more likely to be subject to water damage than one that isn't sealed tight. Quality gun safes that are built well are nearly airtight already

It's a common misconception that gun safes are airtight. This is not true, but the good news is there are ways to create an environment with less oxygen. 

There are many ways to make a gun safe airtight, but there is no one-size-fits-all solution. Here are two of the best solutions: 

Protect your items with the highest quality safes

The first step in doing this is buying a quality safe that has thick steel walls and a door. Most people don't realize that cheaper safes won't have these features, which may mean they're more vulnerable to fire or other dangers than if they had gone with a higher-end model. 

Silica bags against moisture

Another way to keep your guns in optimal condition while inside of the safe is by using desiccant packs made for firearms storage--these will absorb moisture from the air and reduce humidity levels by up to 20%.

Let’s get to know the types of holes in the safe that make it not fully airtight where air can escape

There are air holes in the hinges, there is the air that enters through the handle, which has a spring and mechanism that makes it easier to open. There are air holes that come with the lock or bolt device itself.

What you can do to prevent air from entering the safe is to buy safe seal desiccant moisture packets. You put them inside of your gun safe every month or so, and they help combat odor caused by excess moisture. They also absorb harmful chemicals, such as sulfurous gases (a result of combustion), chlorine, ammonia, smoke, and dust particles from your guns. 

Safe seal desiccant packets can be purchased from airtight safe companies so you don't have to do any searching or buy them off the internet. 

Having air holes might seem like a bad thing, but it's not that big of a deal if you're using your airtight gun safely correctly. Once your guns are in the container, just close and lock it right away. You should then put airtight gun-safe desiccants inside to keep everything dry and protected against humidity as well as odor-causing bacteria.  The single most effective way of accomplishing this is through the use of a safe dehumidifier.

Why airtight gun safes can be dangerous 

An airtight gun safe can be harmful to your guns. It’s important to understand the air circulation in an airtight gun safe is not as good, so you shouldn’t store things longer than a couple of months.

The air hole doesn't allow air from outside to enter inside, and this could cause problems for any kind of enclosed space such as storage units or storage lockers. The air that exists inside will linger for long periods of time and can leave a musty smell on items within it after some time. 

If you plan to keep your belongings in an airtight container or box for too long, then mold and mildew may grow on them because of poor air circulation.

Some air-tights are made with RSC (Residential Security Container) construction designed for minimum fire resistance which means

One important thing you need to know about airtight containers is they are usually used to keep moisture and humidity out. If such a container becomes pressurized, then such an airtight container may get damaged due to overload pressure by accidentally opening air vent holes on the safe or due to abnormal pressure created by changing temperature conditions in space around the safe.  

In conclusion

If you take great care to buy a high-quality safe and keep it properly airtight, your guns will remain in good shape for many years to come. If you don't feel comfortable doing this yourself, then you should speak to a professional about getting the best environment for your firearms.