Like Kenny, for years when shipping longbows I used the carpet tubes with round plywood inserts screwed and taped into place, they worked fine until...............the USPS crushed the carpet tube and broke a bow. Of course the USPS said it was packaged wrong and refused to pay the $900 it was insured for. There went 30 hours of my time and $150 in materials to make the customer another bow. Now the shipping cost is include as part of the original sales price. It hurts to send out a 1K item and not have it protected as much as reasonably possible.
For longbows I now use schedule 40 PVC with a glued and taped end cap on one end, and a screw in cap with a holding screw and tape on the other end. In addition, I take several pictures of it with my cell phone while it is on the USPS or UPS scale to prove how it was packaged. All total, with the PVC tube, PVC parts, shipping, and insurance, it usually costs between $40-50 every time I sell and ship a longbow. Take down longbows are shipped the same way.
For one piece and take down recurves I build a box out of 1 ½’ x 2” fir, 3/8” plywood, and torx wood crews. The inside is padded with bubble wrap/foam and the bow is inside of a bow sock. The plywood box actually cost less to make but takes more time to make. All said, the cost is about a wash with the PVC.