Tobe,what I would reccomend is for you to get a complete lower reciever,then choose between an complete upper reciever or assembling the upper/barrel/etc. Complete lower recievers are still reasonable in price and when matching upper to lower,all you have is 2 crosspins. If you're determined to build 1,be SURE to get dvd or manual with LOTS of pics in order to guide you thru it .