Dunno whether I'm the first person to come up with it, but IMO this is the perfect rebuff to the certainly not untrue, but key-issue-avoiding statement that Guns don't kill people. People kill people, in the way it's used by "right to bear arms" people. Symmetry is beautiful.

If someone replies "But people protect people with guns", you can grin and retort "Well, people kill people with guns".