Rail system (firearms)

Rail systems are small pieces of metal put on any given surface on a gun to allow attachment of some sort of accessory. On them you can attach everything from laser sights to scopes and R.I.S systems. They make the mounting and dismounting of these artifacts significantly easier. Rail systems usually are based on the handguard of a weapon or the Upper receiver. Two types of rail systems for firearms are the Picatinny rail and the Weaver rail.