A flinch that throws shots out are all in your mind. It is done in anticipation of the shot. Humans simply can't react to a shot fast enough to affect the bullet. The shot plan should be something like getting the sights (irons) aligned and hovering over the desired area of the target and steadily build pressure on the trigger until it fires. Do not wait until the sights are perfect and then try to pull the trigger before it wobbles away again. Once again, humans can't react that fast. This does not need to happen slowly, pulling the trigger quickly is fine just don't try to snatch a well centered shot. Your mind will know exactly when the shot is coming and you will grip a little harder, lean into it a little bit and this results in the famous flinch. It is not that your afraid of the shot, your mind is just preparing for it.