Every member of Congress takes a verbal and signed oath to protect and defend the Constitution:
"I do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I take this obligation freely, without any mental reservation or purpose of evasion; and that I will well and faithfully discharge the duties of the office on which I am about to enter..."
Enacting stringent gun control laws, gun bans, gun registration, gun confiscation, etc. are clear violations of the 2nd Amendment and, thus, a violation of the Constitution.
Any congress person who supports such laws should be held accountable for violating their oath of office & violating citizen rights.