Since I live in Lake Havasu City I store my ammo on shelves in an
air conditioned hobby room. This keeps the heat and humidity to a minimum. I reload rifle, pistol, and shotgun so I wanted to keep all the powder cool. It is impossible to get an answer as to what is the highest temperature that is safe to store gun powder from the manufacturers. I found a old can of powder from the 1950’s that stated 95 degrees was the highest temperature to store reloading powder. Does anybody have any current information that has tested proof to give a better answer? If so please advise with source of testing.
I doubt it matters whether the poweder is in a can, or a bullet case. I think once you load a round, the moisture content is fixed. Seating the bullet would be like closing the can. Here is the Army take ... Army Logistician (Preserving Readiness Through Ammunition Packaging) so it seems like they consider 160 °F is their upper temperature limit.
Yep, the Germans made ammo to last the full 1000 year Reich... I'm still shooting (very sparingly) German ball ammo in my Dad's bring-back K98k... it's 198 gr I think, and it has killed whitetail deer. Sellier&Bellot compares favorably. Ball does a number on flesh and bone.I vac seal fresh loaded Ammo, and pack it in ammo cans! I still have stuff from WW2, steel core Machinegun belted still stored in the original ammo cans, and it works just fine!