Here is a Steyr AUG A1 Rifle. I really like this gun. It has a sleak, futuristic look to it. Getting the angle in front and behind the clip was difficult, but I think I did alright. I built this with some pics I found online. I'm not too sure about the measurements. I kind of eyeballed this one.
Very nice for an eyeball job. That sounded funny. Anyway, as for more exact measurements, check out my Steyr AUG/USR: http://mocpages.com/moc.php/20930 ... I've already updated a few things since then, but this is exactly the right size; I got correct measurements from various sites and printed a full-scale profile picture (I'll try to upload soon). When I lay mine on top of it, it fits perfectly. Feel free to use shapes and designs from mine. Keep up the good LEGO CAD work! I hope to see these CAD designs as touchable LEGO sculptures. Good luck!