Nothing. Gun owners would chortle and continue downing shots of whiskey.
There may be some civil strife. Perhaps five dead Supreme Court justices and a few hundred dead congressmen and senators.
A Constitutional Convention would then take place where future attempts to abridge the right to bear arms would result in loss of citizenship and expulsion from sovereign territory. Liberia would be a suitable destination.
I am a law-abiding gun owner, and I do not sit around “downing shots of whiskey”. You are presenting gun owners as the illiterate backwoods thugs the left wants to show us as. If anybody attempts to confiscate my guns, they will find me stone sober and willing to resist by any means necessary.