As long as current ammunition is stored in a fairly dry place (read out of the weather), and not exposed to excessive heat (like you would find by carrying ammunition in a vehicle), it should last almost indefinately.
As far as disentgrating primer compounds, I highly doubt that as well. I think one of the most current primer compounds being used is antimony sulfide. Just from the legal liability standpoint alone I dont think that would happen. Accidental misfires, or a primer that didnt detonate when it should have, and went off 10 seconds later when the gun was possibly in an unsafe condition would lead to huge litigation problems.
I would think more likely they would just require "tags" with serial numbers or such in each powder charge. If you require the manufacturer to place these in each lot of ammo, and then require ammo to be traced from manufacturer to final user so that the BATF would know who exactly it was that owned the ammo.