It seemed like you were pushing the balls into the turret but they were getting stuck at the entry. you might want to add some funneling sheets of plastic or pieces of aluminum to the top of the ball elevator so that not only do they funnel in nice, but the way it enters the shooter in more consistent. From the looks of it, the shooter was not moving at all, but the ball was landing + or - 6 feet in either direction of your target. Making sure the ball enters through the center of the shooter will make it much more consistent
This is espically important since you have a two wheel design, not four. This means that the ball is always going to want to slide off to either side of the wheel. With 4 wheels, the ball stays centered between the wheels so this isn't as big of a problem.