HitTest problem

i ve tired 2 different codes just making my rock go left to the right either way right to the left when it hit the blackL _mc or blackR_mc bar but doesnt work is there something wrong with my code?PLEASE HELP

1,

var MOVE_LEFT:Number = -5;
var MOVE_RIGHT:Number = 5;
var current_direction:Number = MOVE_LEFT;

function moveRock():Void {
this.rock_mc._x = this.rock_mc._x+current_direction;
if (this.rock_mc_.x<0) {
current_direction = MOVE_RIGHT;
rock_mc.gotoAndStop("right");
} else if (this.rock_mc._x>550) {
current_direction = MOVE_LEFT;
rock_mc.gotoAndStop("left");
}
}

2.This one when hit the movie clip it will turn to the right but not what i want to be , i want hit the bar.

function moveRock():Void {
this.rock_mc._x = this.rock_mc._x-10;
//for(i:Number=0;i<495;i+)
if (this.rock_mc.hitTest(_root.blackL_mc)) {
this.rock_mc._x = 500;

}
}

PLEASE HELP !

does anyone knows?

Not so clear about what you said
And in the second code block you said "hit the movie clip ". What dose it refer to by the "movie clip"? the rock?

not exactly sure what you really want, but you may try to chang your code into this: