RE: Shelf life of powder and ammo ?
It is a bunch of bull. I still dip into some cans of IMR-4064, IMR-3031, and IMR-4895 that are AT LEAST 30 years old. My groups are pretty good, and while I've not chrony-ed them, the tight groups would indicate consistent velocities. Having not chrony-ed them I don't know if the velocities are up to par with what the books say they should be, but the dead deer that haven fallen to the handloads apparently viewed the velocities to be sufficient. Kept cool and dry most powders should have remarkable shelf life.
I do not follow the loading industry news closely, so if there are some new powders that degrade in 6 months I haven't heard about it yet.