pluckit

There is a screw on the zoom ring on a Tasco 3x9x50 scope.Does anyone know what this screw is for?

dylan_b

osrry if i cannot explain this very well, but to know what i am taking of you will need to hack a scope apart and see for yourself. basically there is a slot cut in the tube of all variable power scopes(except maybe 2 that i can think of). inside the tube of your scope is a second tube. this second tube holds the reticle and several glass elements in place. when you adjust your scopes dials you are actaully moving that tube around to match your trajectory. but anyway you can change your magnification by sliding that tube back and forth, this is accomplished via a raceway that wraps around its length. that scew fits through the slit in the main tube and settles into that raceway. dont ever remove that screw as your scope might be gas purged and releasing that gas will allow ambient oxygen (with at least some level of humidity) into your scope and it will fog easily.