Modifying Movie clips after they have been created with AddChild();

programming flash
1

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So i’m making a little tank game and i made it so whenever i click a movie clip gets created and is rotated and positioned at the end of the turret barrel. I’d like it so the Movie Clip can move after it has been created.

function shoot(Event:MouseEvent):void
{
    var  newBullet:bullet  =  new bullet();
    newBullet.x = turret.x + Math.cos(turret.rotation * Math.PI / 180) * bulletDistance;
    newBullet.y = turret.y + Math.sin(turret.rotation * Math.PI / 180) * bulletDistance;
    newBullet.rotation = turret.rotation + 90;
    this.addChild(newBullet);
}

So all of that code is fine, but after i have created it i want it to move linear-ly. I’ve tried modifying newBullet but i get a compiler error: 1120: Access of undefined property newBullet.

I thought about making a class, but i am very inexperienced with classes and want to know if there is an easier way to do it inside the .fla.

Thanks ahead of time.
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