I've been storing all my primers in a those sealed green military surplus ammo cans along with desiccant cartridges.  I figured what better way to prevent moisture & humidity from degrading them.  I was curious & asked Googles AI how to properly store primers.  

Wayne

Here's the response:

Ideal Storage Conditions
•      Cool temperatures: Maintain a stable environment between 50°F and 70°F.
•      Low humidity: Keep relative humidity around 60% or lower.
•      Original packaging: Leave primers in their original plastic trays and cardboard sleeves.
•      No metal containers: Avoid storing primers in sealed metal boxes or ammunition cans.
•      Ventilation: Use storage cabinets designed to vent pressure safely in an accidental fire.

So, I then asked, why no metal containers & got this response:

Storing primers in a sealed metal container turns a fire hazard into an explosion hazard.
Pressure and Fragmentation Hazards
•      Pressure Containment: Metal containers are often designed to be airtight and structurally robust. While this protects the contents from moisture, it also allows for a significant build-up of internal pressure in the event of a fire.
•      Rapid Expansion: If the primers are exposed to extreme heat, they will undergo a rapid chemical reaction. In a confined space, the resulting gases expand faster than the container can vent.
•      Structural Failure: The sealed metal container will contain the pressure until its structural limits are exceeded, leading to a violent rupture.
•      Fragmentation: During such a rupture, the metal walls of the container can break apart into high-velocity fragments, creating a significant hazard to anyone nearby and potentially damaging the surrounding structure.