What makes people shoot low with a double action trigger?
It may be a complex set of reasons. One is the long trigger pull of a double action compared to a single action semi like a 1911. The index finger is flexed by a muscle which can act with the other fingers holding the grip of the pistol. So that when the shooter contracts the index finger, he/she also to some extent flexes the other finger causing the pistol to move off target.
A shooter can overcome this tendency by repetitive training to address this issue. Placing an object (like a coin) on the barrel or slide of the gun, balance it there while maintaining the sight picture and dry firing the gun can help.
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