Hello fellow members.. i'm from California and i just purchased my first Lower receiver for the AR15 and i guess i waited too long to start because EVERYTHING is back ordered.  I'm thinking of just building my own upper because all of the uppers online are so damn expensive or they're just sold out and back ordered.  Is there any AR15 gurus' in here that can give me some insight before i start this project? DO's and DONT's?  I can't find anything online so i might just purchase some stuff used on this site.  Any advice can help me out.  Thanks all.

Welcome to the board man.If you are looking for used parts try the EE at the top of the page.You can also find new parts there.

There is stuff online still

Check Ebay, amazon, And the sticked threads at the top of this sub-forum.

I found a Fire control group and grips for 60$ online and also found a buffer tube and 6 pos stock stock online for 35$
If you're looking in the right places you can find a whole rifle for under 600$ (brand new parts)

Where did you find the buffer tube & stock for $35

I'm guessing if he found a receiver extension and stock for $35 it's airsoft crap. UTG maybe as well.

http://palmettostatearmory.com/index.php/ar-15-05/lower-parts/build-kits/moe-lower-build-kit.html

aeroprecisionusa has stripped uppers and palmetto stake has upper reciver parts kits and a barrel. ee for a bcg

Before you do anything, familiarize yourself with California's laws.

If you have the lower receiver, you are probably safe from a new AW ban of the kind enacted 20 years ago.  Be patient and the supply of parts will ease a bit once the gun haters calm down a bit.  My advice is to read carefully the sticky here about how to assemble all the parts.  That will help familiarize you with the few simple tools required and the various alternatives for parts.  Buying parts in a hurry, based on an incomplete understanding of what your own preferences are, is an expensive way to approach your first build.  Ask me how I know.  Assembling the lower is the hard part, with the little roll pins and all.  Assembling the upper is a breeze in comparison.  No need to pay big bucks for someone else's tastes and handiwork. - CW