Powder:
It is possible to mail motors in unopened Estes/Quest motor packs by the US postal service.
You must take your package and packing material OPEN to the post office, show the contents to the post office manager, supervisor, or CMFWIC

. He/they will issue the proper lable(s), watch you pack and tape the box, and take your money. The process takes about 30 to 40 minutes. You have to ask to see the post office manage as most of the counter folks do not know this is possible. But individuals CAN ship motors in this manor, I just did it within the last 2 weeks. Don't try to include AP motors, BP motors only and they MUST be in factory sealed packs.