I bought an irreplaceable loading tool made by A.O.Niedner (in his early days) on eBay, out of Michael Petrov's estate. The flat rate box arrived safely in my mail box- with one end torn asunder and reeking of cheap perfume, empty of its contents. The USPS coughed up what I had paid for it, but what makes me sick is knowing that an important piece of firearms history probably ended up in a dumpster somewhere between here and Alaska.
My advice to all is to tape the living heck out of whatever box you commit to the USPS, and use a box sturdier than a SFRB if the item has any value whatsoever- even if it means paying a little more postage. A small price to pay, especially if the item is made of unobtanium.