The stuff is pressure sensitive
Now what is going to put pressure on them?
. Take quite a 'shock' I think. I've dropped 'em onto cement, stepped on 'em and never once had a pop. Remember when you set a primer in the case, you actually squeeze it into the pocket. The anvil then is 'set' with some 'tension' against the mixture on the final 'squeeze'. Then it still takes the smack of the firing pin to set it off. In my lever 30-30, the bullets (flat nose) are right up against the primer in the loading tube. Every shot gives the primer quite a 'shock' yet don't go off. That said, I still would not store my powder with my primers. In fact, in my workshop, the powder is stored on the left wall in a cabinet, and the primers on the right wall in a drawer. About as far from each other as you can get in the area... plus behind doors as I do other things besides reload in the workshop.
Matt, 125lb of powder? Lucky you
. I've been just trying to find an 8lb jug of Unique. Been holding up ok though, as I seem to manage to find a 1lb jug when I need it.... so far.