Final answer:
In "The Sniper," the IRA sniper uses a revolver to kill the Free Stater sniper after tricking him into believing he was dead.
Step-by-step explanation:
In the short story "The Sniper" by Liam O'Flaherty, the IRA sniper is forced to use a revolver to kill the opposing Free Stater sniper. When the IRA sniper's rifle becomes unusable, he cunningly devises a plan to trick the Free Stater sniper into revealing his position. Upon successfully deceiving the enemy sniper into thinking he has been killed, the IRA sniper uses his revolver, the only weapon he has left at his disposal, to shoot the Free Stater sniper when he stands up over the parapet.