Of course, it's also a good idea to have at least 500 rounds for every weapon in your arsenal, and 1000 rounds for your workhorse rifles. That way, when those with the "I have a gun, so I can get all the food, gold and ammo I want from my neighbors" attitude can become carrion for the vultures in your driveway.
Scouts Out! Cavalry Ho!
Ammo will be worth more than gold WTSHTF.
But your statement is economically meaningless. “Worth more”? Per unit weight? (You’re dreaming).