Circle Dot reticle

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 ...?!
 
Not sure of the dot size on that UTG, but I have issues with dot sights. When using a holographic, a larger moa dot and I am all over because the dot is larger or very close to the size of the bullseye. If I change to a holographic or red dot with a smaller dot, I can shoot much better groups.

I have never been a fan of a dot reticle of any sort on a rifle scope for similar reasons as listed above. Even with a fine dot, I just don't care for them.
 
Ok, I've had a breakthrough. Turns out I'm a bum with a springer! On my Condor this scope is showing its @ass (stacking pellets)...same on my Marauder. I shoot pcp's 99% of the time. Did some shooting at higher magnifications and as the reticle becomes bigger it's more accurate out to 20 yrds (shrug)...just ran through half a tin trying to solve this thing (typical pcp spoiled brat that can't shoot a Springer as good). I really like that small dot on low mag, though...I guess I was trying to make it work.