Sorry to hear about your unhappy experience with UPS mishandling your Mauser. Recently a large number of guns were stolen mid-shipment, in a burglary from trucks parked overnight in a UPS facility, ... maybe UPS needs to clean house among its management so to speak.Probably because it's a Royal PITA. I jus shipped a Mauser Sniper rifle that had been "Sporterized" with a Monte Carlo stock. The buyer actually just wanted the rifle, but the nice stock was a plus he could sell or use. I drove the 45 miles to the UPS after calling first and then waited while "The Manager" was found. I had both license's, everything totally legal, still you would have thought I was shipping a Pit Viper. I paid extra for bubble wrap and the rifle was already in a padded case, but guess what? It arrived broken at the stock wrist and it was not bubble wrapped. I'm still waiting for the claim adjuster to call. I had it insured, of course. Luckily the buyer is a nice, understanding Gentleman.
Also, I believe there's no such thing as too much packaging if you want to make sure what you ship will arrive secure and undamaged. I shipped an item because the buyer--who paid me in person at a show where he looked the item over before paying--was from another state. I made and kept a record of the state ID of the buyer. He provided his LGS/FFL's contact info, and it checked out. I packed the item securely at home--using a foam-interior guncase packed with styrofoam peanuts inside a secure cardboard box--but didn't seal it shut, and took it to a FEDEX facility; FEDEX required I take it to an actual facility, not a retailer who also serves as a drop off for FEDEX. Once the FEDEX service people agreed to accept it, I used a combination of cable ties on the guncase lockhasps and copious packing tape on the outside box to seal it. It arrived sealed at the FFL in the buyer's state who transferred it, and the buyer was very pleased with it.