MS HB621

Prohibits state and federal public servants from enforcing federal firearms regulations (including executive orders and agency rules) that have not been formally adopted by Congress and signed by the President on firearms, accessories, or ammunition manufactured and retained within Mississippi borders.

Makes it a felony (1-5 years imprisonment and/or up to $5,000 fine) for federal agents to enforce non-congressionally approved firearms restrictions on Mississippi-manufactured firearms remaining within the state.

Declares unenforceable within Mississippi any federal law, rule, regulation or order created after January 1, 2020, that attempts to ban semi-automatic firearms, restrict magazine sizes, or require firearm registration.

Authorizes the Mississippi Attorney General to defend state citizens prosecuted by the federal government for violations of such unapproved federal firearms laws.

Amends existing Mississippi firearms statutes to make their provisions subject to the act's protections, including modifications to concealed carry licensing, felon firearm restrictions, and weapons prohibitions.