are you looking to build your upper ? its really not much cheaper to buy the upper in parts not to mention buying the tools to put it together will probably cost more than a complete .
You will need a complete upper w/ bolt carrier group and charging handle , Stripped lower, lower parts kit , pistol grip unless this comes in the lower parts kit , fore arm grip, stock , buffer kit containing buffer, buffer tube and spring , plate and stock ,
Im sure I forgot something
