In the market for a 16-inch upper and I'd like to know what you think my best options are for price/performance.  I'm leaning towards Rock River but I'm open to anything.  Looking for a .223/5.56 chamber.  Thanks!

ar15newbie

Bushmaster chromelined barrel in whatever upper you want.  This has the M16 spec chamber and will shoot anything.

Performance is key, price is secondary.  I only buy Colt's or Bushmaster barrels.

-- Chuck

I agree with Chuck.  Go with a 16" Bushmaster or Colt Lightweight barrel.  You will be happy you did and will remember why the whole design came about to begin with.  I won't waste my time and $ with the others anymore.

Chuck is right, don't waste your time with anything else. Go chrome or go home.

I just watched an old 1966 Army training video on the M-16A1, Functioning and Operation.
 At the beginning of the film, they showed soldiers going through the jungles in Vietnam carrying their M-16's like they were very light, some with just one hand in front of the carry handle.
 These were the rifles with the thinner, lighter barrels. Something has surely been lost in the translation of the  AR-15 between then and now. And that is the meaning of LIGHT.
 Go with the Colt or Bushmaster lightweight barrels.

If you go RRA the only chrome lined barrel they have is the M4 so you will have to get that.

Also look at Armalite.  I prefer the mid-length handguards and Armalite has the mid-length with chrome lining.

RRA isn't bad, but only their M4 barrels are available chrome-lined (and not all of them are, you have to ask for it).  

If the rifle is only for range use, a non-lined barrel is OK, but a little harder to clean and won't last as long.  If the rifle is a "weapon" then chrome-lined is definitely preferable.