I have had two tasco's fail. Both were low end models. One stayed zero'd but the cross hairs went fuzzy within 1 box of ammo, and the other bounced all over the place before the cross hairs blurred. I now have a Nikon Buckmaster with a leupold 1 piece base, and the difference is ENORMOUS. Low light visibility is amazingly better and the scope has taken a BEATING and still stayed dead on. You really do get what you pay for when it comes to optics.