One of the worst things to have in your "gun room"

[Die Judicii]

I've always had issues with this "worst offender" in my gunroom.
And had many run ins with it over the years.
Not so bad during winter,, but a right royal Pain in the Rse in summer.

A ceiling fan.

They just don't mix well with cleaning rods.

[deye243]

Static electricity polystyrene biggest offender

[Wapiti]

Anything humidity-wise, plants, wet area, humidity.
Best place is somewhere that is always air-conditioned, I reckon especially in humid coastal areas.
We don't suffer from that out in the sticks, our humidity levels in ventilated areas are not an issue. Our issue is the places we make humid with our activities, and by shutting a place up where there is moisture in anything.

[CJRBOLTGUN1]

For me its dust, that's just one of the problems of having all your reloading gear in a 3 bay shed with roller doors, you need to cover everything when not using it or it ends up under a layer of red dirt

[Bugman]

For me its dust, that's just one of the problems of having all your reloading gear in a 3 bay shed with roller doors, you need to cover everything when not using it or it ends up under a layer of red dirt

Yes!
Definately dust. No matter where you are reloading.

[GQshayne]

Moisture and mold.