[Slamfire]

I will say no as I have done this on many an occasion. However expect your powder reservoirs to darken over time.

Gunpowder outgases NOx due to nitrocellulose breakdown and there may be other gases due to the inhibitors and stabilizers in the powder. Not all plastics are immune to the stuff and Skeeter Skelton wrote of a reservoir of his cracking and failing after prolonged exposure to gunpowder. There are articles in the 60’s American Rifleman describing the Army’s experience with certain types of plastics being incompatible with gunpowders.

As for the powder itself, heat is the number one enemy of gunpowder, humidity is number two. Powder ages and heat accelerates the deterioration of gunpowder. Sunlight is not good either so keep your gunpowder in the dark. Sunlight is bad on all plastics and rubbers.

Primers are covered with a sealant, should be OK.