Originally Posted by sorral
I found a lower at a local gun shop. I would highly recommend a kit from DelTon.com. It will be everything you need minus the lower receiver. The folks that answer the phone are knowledgeable, and really good at helping you get all the parts you need. I bought a kit from them 2 years ago, I got the parts a week sooner than they quoted me.
Be aware that Del-Ton is a VERY busy shop! They sell different models of uppers and some models are on hold because of lack of parts. If you order a complete upper from them try to find out what is immediately available. I've built two M4's and two A3 HBars with Del-Ton uppers and they are very nice ,affordable, and reliable for a basic AR. My son just cancelled an order he had with them for an A1 upper and went with an A2 light barrel simply because we got tired of waiting for it. We also used the Del-Ton lower parts kit. The trigger group varied in quality. Two of the kits had very good trigger groups and two were quite rough but nothing that a bit of dremel and polish work can't fix. But again we are not talking $200 dollar custom triggers either. If the OP is going to build his own a good place to start is AR15.com. Good build books help also. AR's aren't hard to build if you have a little skill and some tools but some upfront research is a must on any project. +1 on the Spike's Tactical lowers. High quality at working man's prices.