I agree. There is no good substitute for the old genuine GI ammo cans. They have been proven to keep ammo fresh for literally decades. I do use one of the cheap plastic ammo cand for my trips to the range with assorted boxes of ammo, but only because they open far easier. You close the lid on a GI can on a hot day, let it cool off and when the air inside contracts they pretty much vaccum seal and are a pain to get open again.I use both "50" and "30" ammo cans. If you dont mind the weight the "fat 50" is nice.
I've got them stacked, and to keep me from opening and looking to see what ammo is where; I use painters tape and a marker to label the contents. My preference is metal military surplus cans instead of plastic ones sold at big box stores and other retailers. I dont trust the integrity of plastic when stacking all of that weight.
Primers can be exposed to massive humidity, dried and will go off just fine. When made, the primer compound is mixed with water and squeegeed into the cups. The compound is inert when wet, but once dry they are active. I still store mine in ziplock bags to try and maintain a constant level of humidity to keep the SDs consistant.So get this.
Just for conversation sake.
A good friend of mine had to move and gave me all of his reloading stuff from the 1970s.
He hasn't shot since about 1980.
I got a few thousand primers in their factory non sealed packaging. These primers spent over 30 years in a Virginia attic. We have four seasons here, and they change like a rollercoaster. Would you believe that every primer worked flawlessly? Doesn't make any sense to me, but its absolutely a fact.
I still stick to metal ammo cans as I stated above, and in a controlled environment. Although this ammo we all store so cautiously may be more resilient than we give it credit for. I'm not going to find out by testing the limits of ammo I spent my hard earned money on though.