Looking for some insight on the matter. Will be shipping it to be recored for upgraded baffles. USPS? UPS? Next day type thing or?
USPS regulations specifically include silencers within the definition of “firearm” and most people cannot mail any “firearm” capable of being concealed upon a person.
FedEx prohibits it, at least the last time I looked. I haven’t read UPS’ rules recently.
You should also research whether you need to accomplish an NFA transfer to the repairer. I had previously read that the ATF did not consider a return of the silencer to the silencer’s manufacturer for repair to be a transfer, but even if that is true it wouldn’t apply to a delivery to a person who is not the silencer’s manufacturer.
Look at section 9.5: https://www.atf.gov/firearms/docs/undefined/atf-national-firearms-act-handbook-chapter-9/download