I guess I have to ask... what is it about primers setting on a shelf, or in an ammo can, that would cause them to detonate, aside from a house fire, anyway?
I've stored my primers, typically CCI or Winchesters, which are packed pretty densely, in ammo cans for 30 years. They are on a shelf in the reloading room near the floor. I don't shoot my ammo cans... so there is that. I don't throw them off the roof, kick them, whack them with a baseball bat. I don't see the danger. Carriers haul primers in trucks... they see far more vibration and impact from a trip in a truck or trailer than they have ever seen in my ammo cans... and I don't know that I've ever heard of a Buster Brown truck catching fire because he had a sleeve of primers in the truck out for delivery.