Horizontal progress bar width in actionbar

I'm displaying an horizontal progress bar in my action bar. My problem is the progress bar width is not the action bar width, but smaller (but centered). Is that a normal behavior? How can I give it the screen width?

I'm using this in onCreate

    requestWindowFeature(Window.FEATURE_PROGRESS);

and this in my methods

public void setShowIndeterminateProgress(boolean val) {
    setProgressBarIndeterminate(true);
    setProgressBarVisibility(val);
}

Thanks in advance.