A "No Scope" is getting a headshot kill with a rifle or sniper type weapon without zooming in with the scope. The rifle no scope implies long range, but the sniper no scope can be at any range, typically close as a very risky defense against enemies. No scoping is almost impossible in practice, and should only be a last resort, as missing a no scope with a sniper weapon is certain death, especially at close range. In Quake 4, unless you turn it off, you will have crosshair even when using railgun. And before versus the real players, you should practice the weapon in single player before doing this on multiplayer. Machine Gun and Railgun have scopes, while the former is mainly for close range or the back up when stronger weapons are not available, Railgun is mainly used as long range weapon