Guns? they will decline and probably cease to exist in the far future.

Weapons will be the Physical AIs. The future will be that human individuals will poses technology to defeat AI and Physical AI using their kind, meaning AI will be the weapons.

Expensive weaponized electromagnetic devices will also be used including energy directed weapons but since these cost greatly to acquire, it is most likely that the ones who will own these are the state forces, some rich people, and some engineers who can create their own.

Guns, they will be gone in the far future.