This is the schtick to aim well.
The ability to set up and execute a sniping attack, ignoring normal Range penalties. The maximum range depends on your equipment, but several hundred meters is normal for a target rifle. This is a normal Guns attack where you ignore all range penalties, but you may not move as a part of your shooting action.
Sniper also speeds up Aiming. A single shot of aiming will now give the full +3 bonus on your next attack. Additional aim time has no effect. You may not move between aiming and firing, as normal.
Once people know you are there they will quickly take cover, sniping is most valuable during surprise.