I'm using MovieClipLoader to load an external as2 swf file into my as2 flash project, and I'm having trouble getting the original stage size of the loaded swf.

When I run the following code:

var popup:MovieClip = _root.createEmptyMovieClip("popup", 1);
var loader:MovieClipLoader = new MovieClipLoader();
var loadHandler:Object = new Object();
loader.addListener(loadHandler);
loader.loadClip(url, popup); 
loadHandler.onLoadInit = function(mc:MovieClip) {
    trace(mc._width + ", " + mc._height);
}

I get strange width/height values (mc._width=601.95, mc._height=261.15) when what I actually want is the stage size of the loaded swf file, which in this case I know to be 300px x 250px.

Any suggestions appreciated! Thanks