Moisture is always the enemy of ammunition. "Keep your powder dry" didn't end with the invention of cartridges. Same goes for preventing mice damage, they will go after cardboard and build a nest in your ammunition stocks, and as pretty much everyone here likely knows, mice can and will get virtually anywhere.
As for this ammo itself, it's my personal favorite for plinking and small game huniting. Stingers and Velocitors are awesome in a bolt or lever rifle, but that additional velocity isn't always the best for the semi autos when feeding reliability is a major concern as they have caused my semis to ride over the next round in the magazine due to the increased cycle of operation speed. Mini-Mags have always been right in the "Goldilocks Zone" for me that I can feed my Buckmark, 10/22 and DPMS AR upper with >99% reliability.
My Annie still eats nothing but a diet of Eley...