This official US Army M110 Sniper Rifle has all the necessary accouterments: long barrel, scope, and an iPod touch.
You see, that iPod is running the program BulletFlight, available now from the App Store for $US12. BulletFlight is essentially a ballistics calculator that turns environmental factors like windspeed and distance into simple "click" adjustments on the rifle. Five different rifle profiles have been preloaded into the software to factor in specifics like muzzle velocity and bullet weight.
But even more importantly, having a gun app on an iPod finally gives the sniper a excuse to blast AC/DC while clearing an area of hostiles—as if another one were needed. [BulletFlight and BulletFlight App via Engadget]