The most likely response will be for the gun grabboids to try to ban more guns from Americans.
Possibly, in some jurisdictions. But at some point gun owners, esp veterens, will simply not comply. It will start "LA Korean style" with people guarding their kids schools open carry, and it will spread, with police told to back off, and "the 2nd amendment and my DD214 are all the papers I need."
I agree eventually that will be the case but getting from here to there will involve a whole lot of pain. The initial reaction will be for the gun grabboids to demand banning everything.