This needs to go into ammo and reloading, not general.
9mm is the easiest to stock, its a NATO round, cheap, readily available. I consider a stockpile to be no less than 10k rounds. Going to be much easier now that I reload
What do you consider to be the most easily sold ammo? I have been buying M193 in 5.56x45. It is Prvi Pritzan. I have never had any issue with this ammo, but I don't know how others perceive it. I can't find much of any other ammo at reasonable prices right now except steel cased and I am not a fan.
Most easily sold??? As in to re-sell later on?
If it gets to that point I doubt many people will be too picky and will gladly take whatever you have to offer.
With 5.56/.223 ammo I just buy whatever I can find for the best price and try to buy in bulk.