It's been my experience, when shipping packages, via USPS, UPS, and FEDEX they all have asked me what am I shipping/mailing and to sign the electronic claimer that I'm not shipping any hazardous items on the poster; ie aresols, chemicals, etc that aren’t allowed to be shipped by air. Declaring ammunition, reloading and black powder, primers are marked/get the hazmat and ground transport labels. Shipping firearms (FEDEX) are a priority, long guns are generally listed with 3 day delivery; handguns have to be shipped next day delivery.