My FFL received one on my behalf a few weeks ago...via USPS.
I always thought that was the law, but hey it arrived in one piece and i didn't ship it so i wasn't concerned with how it got there.
I had someone pull the trigger on a .300 Win Mag about 2-3ft from my right ear. It was pretty excruciating for a minute or so and i couldnt hear a whole lot for about an hour, but my hearing returned to normal after that.
Never suffered any long term effects, thankfully.
I guess i shouldn't assume it was in a box with packing material. Thats probably a false assumption in this case
I was referring to a private citizen. FFLs can ship via Priority Mail, I believe.