Mac is right on, the triangular boxes work the best, I've received several barrels in them, they work great, just be sure to pack it so the barrel can't bust thru the end. One way not to pack a barrel is in one of the round mailing tubes without enough packing inside. I received one with both ends knocked out and the barrel would slide out loose, was real surprised that UPS didn't repack it or seal it, it was delivered together and undamaged that I could see, but not sealed at all.