Nasty stuff.
5.56mm
I was reading some material on Roman History up to the failure of Rome in the 500s AD. It seems there were quite a lot of pandemics besides the 2 or 3 famous ones, particularly as the weather and growing conditions appeared to get worse not long after 200 AD.
My son and I were recently talking about whether the monster explosion recently of the Sunda volcano would affect our weather. I Googled and found that there would only be about 2% of the amount of ash as produced by I think they said Pinitubo, so not much to worry about. This caused by it being an explosion in water and thus not a lot of dry ash.