Again with the blue...
...I shoot one with the right(or under)barrel and shoot the other with the left(or over)barrel, just as quickly as I can get on target. Then I put one target on the other and mark the holes. This is the only way I can tell of the gun is crossing or shooting wide.
Why is shooting at one target not accomplishing the same thing? It isn't as thought the gun knows it is shooting at a different target and I would think that when shooting at the same target, the shooters hold,footing and posture is set rather than swinging slightly to another target.
If I shoot,check point of impact,then shoot the second barrel;then I have waited too long between shots...
What is too long? In the field, two shots aren't necessarily going to be snapped one right after the other so wouldn't it be more consistent to shoot each barrel with the same amount of preparation and control in order to see where it is really shooting one barrel compared to the other? Also, at 25yds, the point of impact of a 20 bore bullet is very obvious and takes only a second to determine with the naked eye.
