After going through the primer and powder shortage in 2007/8 I have ensured I keep a MINIMUM of 25k on each primer size. My powder collection is stored at 2 residents as I exceed storage limits as a residential dwelling. When I purchased the primers I paid $175/5000 for a total investment of $4375. The value of those primers today would be a minimum of $17,500 if I sold them for all at $140/1000. However, given the fact large rifle primers are selling for $400/1000 right now, that's $10,000 alone.
Other notable investments inclue buying 24 sks's @ $150 a piece. 5 svt 40's @ $225 a piece. Many many crates of 7.62 x 39, 54 and 25 at well under 50% their current value. 5000 round flats of 22lr for $250 bucks or so, now worth an easy $500/5000
Investing into guns/ammo can pay off big time but the threat of government confiscation looming over your head all of the time makes one hesitant.