I disagree with a number of replies in this thread. Not with the overall thrust however that modern handloads are likely shelf stable for several decades.
However it is erroneous to state that nitrocellulose is stable, or that air must be excluded to keep it stable - there is a spontaneous decomposition of nitrocellulose and the conquering of this has been the real secret of smokeless powders success. From the incomparable TL Davis,
Chemistry of Powder and Explosives:
The French found out about the instability of nitrocellulose when they lost two ships, the
Jena in 1907 and the
Liberte in 1911 due to decomposing smokeless powder detonating spontaneously. After this more work was done on retardants, using chemicals like aniline, dephenylamine and the centralite family.
The modern success of smokeless powder in terms of shelf life and temperature insensitivity is due to various coatings that are burning rate retardants and stabilising chemicals.
This is a report of a fellow shooting his 40 year old handloads:
http://castboolits.gunloads.com/showthr ... r-old-ammoFive years is the oldest I have shot.