For the money if you are doing only one build, and tools are limited buying a 100 percent reciver is the way to go. I build my own from blanks but I build a lot and have a full blown shop. If you want to do 4 or 5 builds then you might want to invest in some tooling like a jig and rivet tols. DO a search here as this stuf has been coverd a lot. spending $50 -$75 =ffl sounds a little pricey but if you count the flat and the center support cost say $20-$25 for a premium flat saving $35 -$50 does not seem so bad especialy if you value your time. using a 100% reciver will most likle result in a lot better fist build as well. + it can be sold to some one if it was built for personal use only through a dealer. you can then use that reciver as one to copy if yopu decide to build more.