Very carefully! Yes, referees do make mistakes from time to time and you certainly should ask the question if you are absolutely sure in your own mind it had been hit.
Most refs are decent people who will invariably give a shooter the benefit of the doubt, should any doubt exist.
It?s how you ask the question that?s the important thing ? a belligerent attitude will get you precisely nowhere; neither will you get much joy if you continually question the judgement of referees on the shoots you attend.
If you do, word will soon spread that you are trying to ?steal? birds and gain what could be a winning advantage.
Remember that a referee will position himself in the best place to see the effect of the shot whereas your view will be compromised by the gun in your shoulder and gasses at the muzzle ends from the fired cartridge.
Often what you mistake to be a chip off a target is nothing more than the cartridge wad flying off at an angle.
What I do recommend is that you learn the rules of the discipline being shot chapter and verse, so that you know how to lodge an appeal against a decision and how it will be handled by a shoot jury.
It?s very rare for a complaint to go that far which probably says a lot about the quality and fairness of refereeing at shoots in the UK.