Rifles can be found from expeditions in the wasteland. They require rifle ammo to fire.
Rifles can be fired as a single shot (1) or in a clip (3).
Rifles can be turned into a ceiling mounted trap (Workbench level 4), unlike the shotgun trap they only require ammo and do not need to be armed before hand. Also unlike the shotgun trap they can be activated multiple times and if enemies are spaced out can take out a whole group of raiders. The trap requires motion sensor to be crafted first and is one of the most advanced recipes requiring the most components.