I support the Second Amendment, however I do also comply with existing laws. Just because one doesn't agree with a law doesn't make that law invalid. As my livelihood is predicated on me not becoming a prohibited person by way of tripping over some charge trumped up against me unless I have tons of money to pay lawyers to fight it for me, I choose to fight the laws working within the law writing legislators, for example.
First off, believing a law is unjust or in violation of the Constitution doesn't make the law invalid and unenforceable until it's been completely adjudicated and "ratified" if you will by the SCOTUS. You can still be arrested, go to jail, become a prohibited person (depending on what "invalid" law is being violated), spend a ton of money on lawyers to defend yourself and maybe, in the end, be proved right.