Hello,
This is my first post, so if it has been asked before and explained in detail, please just guide me to the right place.  I am trying to plan out an upper/lower build and was seeking some advice.  The plan is for an 18" barreled upper.  I was thinking of going with a noveske lower, and upper, maybe with the noveske barrel and matching bolt.  The purpose of the rifle is for targets at distance (as far as I am capable), and maybe varmint.
Questions:
1.  Good manufacturer for parts?  Barrel seems high on price, so is it worth it, or are there other barrel manufacturers out there that do it for less with equal quality?
2.  When building an upper, with a new barrel, upper, and carrier assy..is headspacing an issue?  I do not see it mentioned much when people are discussing their builds.  What exactly does a matched bolt give me in this particular platform?
3.  I was considering Mega upper and lower, or maybe the Olympic Arms matched (note, matched, not match grade) upper and lowers (I can tell some people aren't too fond of oly on here, but I have been pretty happy with my current rifle made by them).
4. Was going to go with the Stag/CMT lower kit as well.  Lots of people here seem to like them, any other lower parts kits and reasons why they are equal or better?

Lots of different builds I have been reading through on here, and I noticed questions like these  (nothing as specific though) get asked with frequency.  So again, any guidance would be appreciated.

Thanks,
Boom

Quoted: Hello, This is my first post, so if it has been asked before and explained in detail, please just guide me to the right place.  I am trying to plan out an upper/lower build and was seeking some advice.  The plan is for an 18" barreled upper.  I was thinking of going with a noveske lower, and upper, maybe with the noveske barrel and matching bolt.  The purpose of the rifle is for targets at distance (as far as I am capable), and maybe varmint. Questions: 1.  Good manufacturer for parts?  Barrel seems high on price, so is it worth it, or are there other barrel manufacturers out there that do it for less with equal quality?My experience has been with Wilson and RRA barrels (also made by Wilson).  So far I've been happy, though I'm not a precision shooting.  I've heard good things about Noveske and PacNor but can't personally vouch for them. 2.  When building an upper, with a new barrel, upper, and carrier assy..is headspacing an issue?  I do not see it mentioned much when people are discussing their builds.  Most will say that a new bolt and new barrel will headspace fine.  I always say better safe than sorry.  I would check it after the build to be sure.What exactly does a matched bolt give me in this particular platform?I've gotten the impression that this is somewhat over-hyped, but maybe someone else can chime in on this. 3.  I was considering Mega upper and lower my favorite, or maybe the Olympic Arms matched (note, matched, not match grade) upper and lowers (I can tell some people aren't too fond of oly on here, but I have been pretty happy with my current rifle made by them). 4. Was going to go with the Stag/CMT lower kit as well.  Lots of people here seem to like them, any other lower parts kits and reasons why they are equal or better?  I like RRA and Stag.  Both use nice roll pins and that is enough to save a lot of headaches. Lots of different builds I have been reading through on here, and I noticed questions like these  (nothing as specific though) get asked with frequency.  So again, any guidance would be appreciated. Thanks, Boom

The barrel is the most important part. this will give you an idea as to the general classifications of barrel quality.
www.ar15barrels.com/prices.shtml

Normally an AR barrel is headspaced.

Buy Mega over Oly if you can find the Megas.

Stag is probably the best buy on lower parts kits now.

There is a build it yourself forum that you may want to look over.