BetaBarrels depends on RedLib to work, it can be found here.

Make vanilla barrels behave like modded barrels! With this plugin, any barrels that are placed will automatically be converted. You will be able to store up to 2 billion of one item type in them. To add an item, simply right-click on the barrel with the item you want to insert. You can shift right-click to insert all items in your inventory. To remove items, simply left-click the barrel to remove one, or shift left-click to remove a stack.