I recently bought a Gen 3 G17 and I got to shoot it for the first time today. I am having trouble with shooting consistent groups with it from about 20 ft. For instance my first shot is almost dead center, second is about 3 1/2 in to the left, third shot 2 in down 1 in left, fourth is 2 1/2 in low, fifth 2 1/2 in left, ect. To the best of my ability I am aiming at the exact same spot. I have no idea what I am doing wrong. I have rifles and from the exact same distance I could put all my shots in a 1 in group. Does anyone know what I am doing wrong?