Ah, I think I see what you are saying but it I present in another state. Safest bet: call the ATF. Or better, if not in a hurry, get an answer from them in writing.
Things may have changed a bit, but about 5 years ago I purchased a new rifle at a gun shop in Michigan. I wrapped it, took it to the local Post Office and shipped it to myself in California. The clerk in Michigan said this was nothing unusual. More recently I had a handgun shipped to me from Illinois. Had to use an FFL at both ends. This, I recall, is because it was a handgun, not a rifle.
If you do need an FFL, and your destination is near San Diego, the best is Gussler’s.
I’m not a licensed gun dealer, but I recently shipped a 19th century black powder muzzle loading rifle from Salt Lake City to the Chicago Area through the USPS. I think this was a “special case” because it was not subject to many of the regulations. Before I tried to ship it I made numerous phone calls to determine this was the best way to go. I definitely received conflicting information from many individuals at a variety of organizations (USPS, UPS, FedEx, DHL, United Airlines,…).
I had UPS package it up and then I took it to USPS for shipment. It took over 3 hours total. It was not a good day for government competency or efficiency.