Um, the military drives their ammo all to heck and back, and the truck driver delivering the factory ammo from the factory to the store drives probably over a thousand miles to get it to you. And, the container the ammo is stored in isn't going to make a great deal of difference unless you make a habit of flipping your vehicle end over end for several miles at a time, every day. Gravity will more or less keep the powder in place. Any movement within the case itself will happen regardless if the ammo is stored loose or in a holder of some type. The difference in vibration is probably not more than 2 or 3 times as much.
It would have to be several orders of magnitude worse to make any kind of difference, and it would take a LONG time to make a difference even then.