There are a lot of large cities that don’t have handgun bans, and those cities don’t have any greater problems than DC or Chicago or NYC. For example, Houston and Dallas don’t have handgun bans.
So 51% of all gunshot injuries are self-inflicted or "return fire"?
Mostly because the State Legislature won't let them. And of course because of provision of the Texas Constitution which reads:
Every citizen shall have the right to keep and bear arms in the lawful defense of himself or the State; but the Legislature shall have power, by law, to regulate the wearing of arms, with a view to prevent crime.
Art. I Section 23. Texas Constitution.
Notice only the Legislature has the power to regulate the wearing of arms, not the cities or counties. That makes the big city police chiefs as unhappy as the Second Amendment makes the FBI director, maybe even more unhappy.