They *have* to put this blurb in there
The contents of this document do not have the force and effect of law and are not
meant to bind the public in any way. This document is intended only to provide clarity to
the public regarding existing requirements under the law or Department policies. This
guidance does not alter in any way the Department’s authority to enforce federal law and
is not intended to, does not, and may not be relied upon to create any rights, substantive
or procedural, enforceable at law by any party in any matter civil or criminal.
It's the result of Trump's 2019 EO
Executive Order on Promoting the Rule of Law Through Improved Agency Guidance DocumentsSection 4:"each agency shall, consistent with applicable law, finalize regulations, or amend existing regulations as necessary, to set forth processes and procedures for issuing guidance documents. The process set forth in each regulation shall be consistent with this order and shall include: a requirement that each guidance document clearly state that it does not bind the public, except as authorized by law"
It doesn't matter though. BATFE position is that this isn't rule making or a change to any law. It's guidance on how they will interpret and enforce the existing law. They will interpret some firearms that have pistol braces to be SBR instead of pistols.
Which ones they call SBR is based on arbitrary, subjective, unspecified caliber, weight, length, length of pull, attachment method, which brace, sights and scopes, and other accessories. Basically, if they want to they'll call it an SBR and throw you in the pen. Good luck.