Manufacturer's warranty won't cover shipping and won't cover getting it into and out of the US.
Shipping a gun to the US for repairs is considered a "Temporary Importation" and requires a Temporary Import Permit that is issued by US State Department.
Without getting that permit, you might be able to smuggle the gun into the US... BUT... the manufacturer won't be able to legally ship the gun back to you because without that Temporary Import permit (for repairs) they have a legal problem... They are in possession of a firearm that was not legally imported into the US and for which they can't legally get a permit to send it back out. If they are caught shipping it back to you it is considered an illegal export and they are in deep trouble... so they'll freeze the gun and you're screwed.
Mark