The phyical difference in operation,is that a crossbow is fully "cocked" (drawn back fully to rear position),while the drawloc holds the bow almost at rear and still has to be drawn slightly rearward more before releasing the arrow. At least that's MY understanding the way it works. Since it's not totally drawn,that's how they get the "loophole" around conventional crossbows. If my understanding is incorrect I'm sure someone will explain it better.