Had this discussion a while back - still kinda unresolved
The weapon is always a lot more accurate than the shooter until proven otherwise.
These are your only variable - if the gun is benched and accurate then your job or your coaches job is to bring you the shooter up to speed on accuracy.
If you look at point B on the diagram B is an endpoint not a corner. If its a fixed sight gun or a sight adjusted gun and a good shooter can hit x s using a PROPER sight picture than you need to be able to do the same thing.
it's like fingernails on a chalkboard when i hear of people taking files to gun sights to compensate for their poor techniques. If your consistantly shooting one way or the other using different guns it you - change your technique.