Can someone explain the best application for a circle dot reticle. I just got an UTG model 1-8x28 multi range combat scope for my Springer (340 luxus pro compact) that I'll be using exclusively for short range (20yrds max), and I can be spot on with the dot covering the bullseye and I'm only getting within the general vicinity of it. Swapped out scopes to see if it's the gun (even cleaned the barrel) and I'm hitting the red true. Going back to the UTG circle dot and I'm all over the place ...?!