A lot of people don't understand what is involved in changing the Constitution. Because the 2nd Amendment is part of the bill of rights, changing it is a heavy lift.
First, you have to get 2/3rds of the House to agree. That's 290 votes. In a body that is struggling to get a 218 vote simple majority on most things.
Then you need a 67 vote majority in the Senate, a body hamstrung by the 60 vote filibuster.
Assuming you get both of that, it still has to be ratified by 38 states in order to take effect.
Alternately, 34 states could call to re-write the ENTIRE constitution... Something which the founders wanted to have happen every 20 years or so...
But then that still needs ratification by 38 states...