Pistol-shooting-chart (Training aid)- How I found out I was tightening my grip while pulling the trigger. Tight groups but always pulled that direction. After using the chart, I could feel what I was doing and corrected it!
I finally found it!! It took some searching, but I finally found the website for this "hidden gun case mirror". The company is called Tactical Walls, and they have a lot of different options for stuff like this. This particular set up is only $375!!