For prints that size, I'd favor the mailing tubes sold by Uline, among others. I'd even do it for anything much past 13x19 size.
What Ive done is to cut a piece of interleaving material (like an acid free "glassine" paper) to a size slightly wider and longer than the print, and then fold a flap back over the short side of the print to form a kind of "envelope" that will stay on the print. The interleaving is generally placed against the back of the print with the flap over its face.
I then stack the rest of the prints in the shipment, all similarly protected by interleaving, atop each other, and roll them gently to fit the diameter of the shipping tube. I roll the prints with the back of the prints outward; the interleaving of each print's back protects the face of the print below. There's no reason I can think of why the interleaving couldn't be placed on the image side of the print, and/or the prints rolled image-side out. The tube itself is several inches longer than needed so that there is empty space at each end once pack. A crumpled up bunch of interleaving at each end, plus the redundant interleaving at each end of the "roll" of prints, cushions the "cylinder" of prints.
This has worked well for me. I think shipping very large flat prints is just asking for trouble. Something smaller and more compact, like a tube, has to be safer. It can survive being tossed or dropped without damage, if properly packed internally. And the prints, if laid flat by the recipient, will unbend quickly and sufficiently enough to enable whatever matting/presentation they choose.