Well someone to reverse engineer the gun and figure out the dimensions, build maybe multiple prototype to see if it works, then maybe 70k for the mold. So maybe 100K plus to develop and put in production. so maybe they sell whole sale £50ish each, costs them £20 to make them. so they have to sell several 1000 just to break even let alone a profit and they will loose production time on existing more profitable models. so that's why no bodies done as you notice all the current AUGs other than KWA and GHK are clones of TM designs.