all above are popular rifle rounds in this order .308, 270, 6.5, and .243 in my estimation, based on what I've seen people owning out there over the years. Not that any of them would be bad to add to the barter stockpile.
Can't go wrong with any of the shotshells either.
my friend picked up a used 410 side by side a couple months ago. I've been trying to get it from him since he bought it...no dice. haha