Broken tow missiles'

does anyone know the tow missiles have a cork screw effect when leaving the missile housings rather the flying straight like they do in vidio of actual firing of the missile . I noticed it in the Bradley , M901 and the LOSAT . I have watched several video’s of practice firings but not one time did it swirl around or go of course. So it has to be something Warthunder is doing on there own . Diverting from reality to something else. I wonder why they did this because it reduces the effectiveness of the weapon . yes maybe that is it .If so I wish they would say so . That way I would know not to use them