The hard shipping tubes work great, just make sure they're the heavy ones, and use lots of tape on the ends, I prefer to staple the caps in or use wood caps. I got one barrel that had completely punched both ends out of the tube, all the packing was gone, fortunately UPS kept it together and made delivery on it. I was real surprised that they made no attempt to rewrap it!!
I've never liked newspaper for packing, I use bubble wrap for barrels, it doesn't draw moisture and provides more cushioning that paper. I also think it's less abrasive on the thin bluing that's on em, all the vibration involved with transportation can make bare spots after the paper compresses slightly and the barrel is a little loose inside the tube.

Tim