I am planning on building my first AR in the very near futurehoughts
I will mainly be varmant hunting and target practicing with it.  I like to take some long shots so accuracy is imporant to me, as is trigger pull.  It must be reliable and versital.  I will take some long hikes with it, and also plan on using different accessories on it that I use on some of my other guns right now including a laser, tactical light, red dot scope, high power scope, night vision scope, and bipod.

So far I think I want the following:
A3 flat top upper
18" or 20" threaded barrel
4 rail floating handguard
6 position collapsable stock

I am unsure of all the rest and also the brands on the parts that I listed.  Please make any suggestions or let me know what you are thinking, as well as which parts you reccomend and where to get them.

Thanks in advance for the help.

In before the use the search function crowd.

Check out the Build it yourself foarms. Love to get those questions!

16" barrel, midlength gas system, flat-top

Quoted: 16" barrel, midlength gas system, flat-top

Is there a difference between midlengths and standard length rifles regarding the gas system?

Quoted: Quoted: 16" barrel, midlength gas system, flat-top Is there a difference between midlengths and standard length rifles regarding the gas system?

Yes midlengths use a midlength gas system and standard length rifles use a standard length rifle gas system.  Also, carbines use a carbine length gas system.

If this should be in the build it yourself forum would an Admin mind moving it there for me.

What lengths are  considered standard, mid, and carbine?

Quoted: If this should be in the build it yourself forum would an Admin mind moving it there for me. What lengths are  considered standard, mid, and carbine?

carbine barrel= 16" or shorter
Midlength barrel=18"
Rifle barrel=20" or longer...ie, 24"varminter barrel

Midlength gas system can be had on 14.5-18" barrels.
CMMG has 18" barrelled uppers with either midlength gas system or a rifle length gas system. I have had their 18" middy and it was very accurate. I have one of their 18" rifle length gas system uppers now.  

If you dont want a boutique barrel go with a CMMG 18" medium contour w/midlength gas system or rifle length gas system then install a 4 rail freefloat forend. If you want back up irons go with the F marked FSB and use a rear BUIS on an flattop upper.

JMHO, YMMV

Is there an advantage to one gas system over the other?

Quoted: Is there an advantage to one gas system over the other?

On the 18" and less barrels the midlength gas system gives a smoother recoil pulse than the short carbine system. That means its easier on the shooter and weapon, getting back on target quicker and so quicker follow up shots. IMO

An 18" barrel w/rifle length gas system gives you the rifle length sight radius.

Any and everything available for AR type weapons boils down to the end users druthers.

I will definatly get the mid length gas system.  I talked to the folks at DPMS earlier about several differnt kits they offer and it seems like they have a different kit or upgrade for everything I can think of.  I noticed they have a banner on this site so I assume they are a good place to buy from.  How do you feel about their parts?  i also have a friend who is a bushmaster dealer so I need to go see what kind of prices he can get me.

You wouldn't have any extra barrels you want to sell would you.  I was wanting and 18 or 20" barrel, threaded with recessed crown.

I have just been looking at barrels from DPMS and was interested in a 20" bull from them.  Between that and custom machined stock one what would you suggest.  What kind of accuracy would you expect at 200yards?  I was also wondering about price but I understand if you don't want to post that on here.  Thanks

Try and budget in some iron sights too.  post pics when your done

Hey I wanted to thank everyone for the help.  I finished it this past week.  Ended up with a flat top a3 upper, superior arms lower, 6 position butsock, 4 rail free floating hand guard, 18" stainless barrel threaded with a2 flash hider, and a 3-12 power tactical scope.  I broke in the barrel, and started a little more serious shooting and it produced groups at 100yards where all the holes touched after I got the scope adjusted.  Future plans are tactical sling and mounts for the rails, iron sites for backup.  I will probably also change but stock because this one isn't as solid as I would like.  I am going to a place where I can shoot some longer distance this week, so we'll see what it can do at 200 and 400 yards if I get a chance.  I forgot to mention I had to do just a little trigger work.  I kept the same angles on the hammer and sear, but I smoothed them up a lot and polished them both, as well as shortened the pull using the set screw in the lower receiver.

we need pics!