My first AR is now complete and waiting for the first dry day to visit the range.  The build was fairly easy thanks to the instructions found here.
The question I have is this - is it normal to have a slight gap between the buttstock (regular A2) and the lower receiver?  There is almost 1/16" there even after I tighten the heck out of the bolt.

here is a pick of my a2 butstock on my lower its tight though hope this helps
http://img349.imageshack.us/img349/3745/dsc002346nt.th.jpg

Make sure that the buffer tube is screwed in all the way in and you didnt screw the buffer tube onto the body of the buffer retainer it should just touch the little nipple on the buffer retainer, if it touches the fat part of the buffer retainer you could have a gap because the buffer tube is not all the way in.

Thanks for passing along some of the finer points of assembly!!  
I'll take it apart tomorrow and figure it out with your ideas in mind.

As it turns out, there was crap on the threads that needed to be cleaned off !!
All is well now.