I also have a Thompson Center Encore with a Nikon scope. When I first mounted the scope with the see thru rings I had no problem getting the gun sighted in. The next year I switched to the Red Head scope rings and I got the gun boresighted and went to the range. I was shooting 2-3 feet low, not even on the paper. Then just this year and bought a different brand of scope rings and the same thing. I was shooting low and by time I got close to dead center my scope was adjusted all the way up. Next year I'm going to try shooting the blackhorn 209 with the Hornaday sst bullets. I know there is nothing wrong with scope.