I thought after posting my last comments on the red dot sight, that the feature of the minute of angle of the dot, could be utilized on a DR that was having trouble with regulation, in the manner of the two sight system on the Pedersoli. For instance if the bullets were striking 4" apart at 100yds, the sight could be adjusted so they were both striking on opposite edges of a 4" dot. I am not suggesting that this is the prefered option but it could be a solution for somebody with a cheaper gun that was not worth spending a lot of money on. Obviously you would firstly have to check that they had not crossed in closer.

Good Shooting, Ian.