Ammunition can not be shipped by the USPS

UPS regulations. The box must be appropriately labeled and taken to a UPS Customer Center, not a USP Store, or through a UPS Scheduled Pickup Account
https://www.ups.com/us/en/support/s...s-materials-guide/how-to-ship-ammunition

You can also ship with FedEx Ground but there is a pre-approval process

More here
https://www.easypost.com/blog/2025-05-07-how-to-ship-ammo