Humidity is a key factor. Attics with extreme heat are not good. Damp basements aren't good. Air conditioning and temperature of 67 to 71 should be very good with humidity of say 30 -35 %. And keep the weapon out and try to keep the belt loops from being squashed flat.
These steps should keep you in good shape.
Others may tweak these suggestions.
My 2.5 cents
Jack
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