I have been keeping it in the garage for 25 years and don’t plan on changing. It's ammo as long as it stays dry the heat is not going to hurt it. Where do you thing they keep in in the Middle East? Up a camels butt?
They are still using ammo from back in the 40"s.
Heat and humidity are what shorten the lifespan of ammo. Humidity levels in the Middle East generally are very low, so heat alone won't be as big an issue. Here in OK, we all know how humid it gets.
As for the justification that they're still using ammo from back in the 40's - so? Does that mean all ammo will be as viable after long-term storage in a warm and humid environment?
If you don't have room for the ammo inside the house, then it becomes a moot point. However, if you do have the means to store ammo indoors, why not do that and remove the heat/humidity factor from the equation?
Too late...now we know where to find alll the ammo...Wait- I want to change my answer. I don't have any ammo.