BSA rifle scopes are produced by BSA Optics, a British Company with a long history. BSA Optics manufactures scopes that are relatively inexpensive. The basic operation of BSA scopes consists of sighting in the scope, adjusting the power and setting the scope for parallax error (not all BSA scopes are equipped with parallax adjustment). Parallax error is an optical illusion of target movement caused by a change in the shooter’s line of sight.
Sight in your BSA scope with the adjustment dials on the top and the right side of the scope. Turn the top dial clockwise to bring the crosshairs down and counter-clockwise to move them up. Turn the side dial clockwise to move the crosshairs left and counter-clockwise to move them right.
Adjust the scope's magnification by rotating the variable power ring near the eyepiece. Set the desired magnification by aligning the desired power with the dot on top of the scope.
Set the parallax adjustment dial on the left side of the scope (if so equipped) to the range of your target.