Ammo storage and cache-ing

[sjohnson]

Colder is better for stability of any chemical compound. Since smokeless powder is a complex chemical compound that includes nitro compounds, cold storage is a good thing.

Cold use may not be.

[kernelkrink]

The burning of gunpowder is a chemical reaction, most chemical reactions slow down when cold and speed up when hot. Very cold, less "oomph" and very hot more "oomph" behind the bullets. In normal temps survivable by humans you will probably notice the performance difference only at the two extremes.