I have sent 3 firearms back to the factory for repair. All 3 times they went USPS. 2 pistols and a rifle.
The handguns were in self address boxes furnished by the maker.
S&W front frame crack.
Ruger Blackhawk for broken transfer bar .
Remington 700 for chicken **** finish.
All were returned to my home by USPS.
All three did require signatures to be received by me.
The rifle would be fine, but while I have seen mention of an exception for mailing handguns just back to the manufacturer by the owner for repairs, I can't find anything on it in the USPS manual. I've even seen posts from people who have been told that by postal employees, but I'd love to get the citation.
Even Title 18 of the USC explicitly states:
Such articles also may be conveyed in the
mails to manufacturers of firearms or
bona fide dealers therein in customary
trade shipments, including such articles
for repairs or replacement of parts, from
one to the other, under such regulations
as the Postal Service shall prescribe.
that's in the book FFLs get that covers the GCA etc. It may come from this section of the GCA:
this paragraph and subsection
(b)(3) shall not be held to preclude a
licensed importer, licensed manufacturer,
licensed dealer, or licensed collector
from returning a firearm or
replacement firearm of the same kind
and type to a person from whom it
was received; and this paragraph
shall not be held to preclude an individual
from mailing a firearm owned
in compliance with Federal, State,
and local law to a licensed importer,
licensed manufacturer, licensed
dealer, or licensed collector;
But that section does NOT say you can use USPS, and elsewhere in both the federal law and the postal regs it makes no such exceptions.
If that language is out there I'd like to see it. Maybe if the manufacturer generates the labels it's somehow seen as them mailing it to themselves, but I'd love that citation. The only thing I can think of is a USPS ruling that they made for that specific case where the manufacturer makes the labels. That's my only swag as to why it would be OK.