I'd say the recent price hikes are due to panic buying and hoarding.
But I seem to remember ammo prices started going up quite a bit in the 2006-7 year range. That was mostly due to the increase in metal prices.
Scrappers were stealing people's AC units and all sorts of other stuff to trade in "scrap" metal, as far as I know this is still happening.
We do need to take into account the fact our currency has halved in value in the last 20 years.