Italiansxs would you please explain what you mean by cooked. In my experience 120 degrees would not affect a load very much unless you are shooting it while it is that hot.
I be glad to explain:
When ammunition becomes overheated over a period of time it is my understanding it causes the powder to break down. This breakdown can have a severe impact on pressures. 120 degress is the outside temperature here I don't know exactly how hot it gets in the garage. Therefore it is generally recomended that ammunition be stored under cool dry conditions. I don't think it's necessary to explain the 'dry" part.
We store canned good in cabinets in the garage. If we forget to remove some before the Summer months they will be ruined for sure and have to be discarded.
Jim
