I use the cheap plastic gun cases that I wrap in two layers of heavy cardboard. I also will use a Leg of Mutton case for doubles that I wrap in bubble wrap and then heavy cardboard box. For barrels only shipment I use modified PVC pipe with screw on ends with bubble wrap around the barrels inside the pipe then bubble wrap around the pipe that is placed inside a heavy cardboard box. You can not over pack but you certainly can underpack.