The story begins with descriptions of "heavy guns ... machine guns and rifles" firing across the streets of Dublin during the Irish Civil War. Immediately, then, these guns symbolize and foreshadow the violence and death to come in the rest of the story, which is primarily carried out by the protagonist, a Republican sniper.
The sniper is directly responsible for the deaths of three people in the story. First, he shoots a machine gunner in an armored car. Then he shoots the female informer who had alerted the man in the turret to the protagonist's location; she falls "with a shriek into the gutter." Both of these deaths bring little to no emotion in the sniper, who at this point is only concerned about his own survival. Towards the end of the story, he shoots an enemy sniper that has been planted on an opposing rooftop. As the Republican sniper shoots his enemy sniper, he lets out "a cry of joy." The enemy sniper falls from his rooftop and lands on the ground below with a "dull thud." The body of the enemy sniper is reduced to a horrifying "shattered mass." Finally, as the "lust of battle" subsides, the protagonist becomes "bitten by remorse"; he curses the war, himself, and everyone else.
Moments later, in the dramatic climax of the story, the sniper discovers that the man he has just shot and killed is his own brother. Upon this revelation, the symbolic significance of the guns in the story deepens. Whereas before the guns are symbolic of chaotic, mindless, primitive violence, they now become symbolic of the idea that violence is self-destructive. Indeed, the sniper has inadvertently used his gun to kill his own brother. We are not told what happens after the sniper makes this discovery, but we might assume that he will be devastated. The violence that he found moments earlier, in the heat of battle, somewhat exhilarating, he must now realize is only self-destructive.