The ATF thinks its being cute by calling them rules instead of laws, but the ATF (and all of the other DC TLA agencies) which are part of the Executive branch ARE MAKING LAWS WHEN THIS IS THE EXCLUSIVE ROLE OF CONGRESS.
Justice Clarence Thomas (the best one on the court) agrees with you.
The Congress has always given some leeway to agencies to interpret law and make rules.
The question is: How much leeway? Is the Agency significantly changing the intent of the law Congress passed?
The ATF under Biden made changes in the law. Some of those changes have been shot down by the courts. Some have been upheld. Some are being reversed or corrected by the Trump administration.
It is a big difference if the Agency changes the form used to apply for an importation license, or if they decide to not allow importation of something allowed by law.
For decades the Congress has given more and more power to the administrative state. It is a violation of the separation of powers doctrine. That is changing under the current Supreme Court.
I have long said that we need an amendment to the Constitution that clarifies that no agency, authority, board, commission, committee, department, division, office, et created by Congress shall have the authority to pass any rule or regulation with the power to punish, or fine any person or company with punitive, monetary, or imprisonment.