As of 2015, it is legal to ship 500 .22 rounds in properly packaged and marked boxes. UPS.com ships small arms cartridges that don’t exceed .50 rifle or pistol rounds or 8 gauge shells.
According to UPS.com guidelines, shippers put the box of ammunition in a tight-fitting box and then pack it inside an outer box fixed with partitions. Partitions help create a snug fit to prevent accidental discharge. The sealed box is marked “Cartridges, small arms” and “ORM-D” inside a rectangle that is 1/4 inch larger than the letters. UPS.com provides an ORM-D sticker image for printing. UPS only accepts ammunition packages at its customer centers or through a scheduled pickup service. The UPS Stores do not handle shipping cartridges.