Borderlands (JP)

Borderlands is a game all about guns, there are millions of them and you will be given some for completing missions, enemies killed can drop them, you can find them in the larger chests (Red with rounded corners and the large flat silver boxes) and you can also buy them from the red weapon vending machines.

You can sell guns at any of the 3 types of vending machines (Guns, Ammo and Med) by pressing to move over to the sell tab in the vending machine. All guns sold in vending machines count but you cannot buy back a gun and sell it again to increase the count. You can buy guns from a vending machine solely to sell for this achievement however.