Well, let's lay it out;
Effects that would adjust it;
Moving
JJ/Falling
Heat
Torso/Arm twist shifting
The hardest point would be moving first. Full speed running should be the biggest factor scaled by the speed you move. Faster you go, the more wild it gets. This alleviates some more static position changes down to a minor nudge - but not as pinpoint as standing still.
JJ and Falling should be approached in different sphere, but mentioned together. a JJ boost ought to be noticeable while its on and adding it to running makes it wild to say the least. Falling should be less as physics demands a pretty static rate of falling regardless.
Heat should be a scaled measure. Less heat, less noticeable - but if you run hot the shots just become wild as a penalty of it.
Last I want to at least urge including torso twist and arm movements slightly but not by much. Adjusting your aim and direction you are facing should have a penalty but nothing drastic. Just a minor quirk that adds up in the greater scheme but shouldn't make it impossible to turn and hit someone fast. Just make it so you spread your hits slightly.
Variables shift from weapon to weapon - where your targeting would only show the largest cone of your equipped weapons.
Some weapons like Pulse Lasers which are intended to maintain good accuracy would have smaller comes where others like an Ultra AC would suffer from a larger one.