Hi everyone. After searching all over the web for forever i can not seem to find this scope setup i have. It is a leupold 6.5-20x40. It has turret knobs and a really really fine straight line reticle. However before the power adjustment there is an incert threaded in that says premier 18x40 and was curious what this did and if it is a great add on. Last i knew one previous owner used it for silloette shooting on a 7mm mag. Any thoughts would be greatly appreciated.