Don't know if many folks are aware of this yet, but ATF Form 1's and 4's are now mailed to Portland, OR. Info (as well as updated forms) can be found at:
https://www.atf.gov/resource-center/new-mailing-addresses-many-atf-registration-forms
https://www.atf.gov/resource-center/new-mailing-addresses-many-atf-registration-forms