Been looking at LW-upper configs for AR ...Yr' pref's?
The main weight savings will come from the barrel, there is very little to be saved elsewhere on the upper.
A polymer lower, like the Cav Arms (they are out of business and this lower is made by GWACS Armory in Tulsa now) will save you about a pound.
I'm building a lightweight AR with a GWACS lower and this barrel.
http://www.shop.ar15hardware.com/16-556-Mid-Length-Light-Weight-Melonited-Barrel-ALP16C...
Planning to use a Bushnell TRS-25 red dot sight with plastic handguards to save weight.
Complete thread:
- Been looking at LW-upper configs for AR ...Yr' pref's? - 
John Meeker, 
2012-10-03, 11:56 
- DSA 14.5" mid length goodness. - Rob Leahy, 2012-10-03, 12:57
 - Been looking at LW-upper configs for AR ...Yr' pref's? - Alfred John, 2012-10-03, 15:26
 - At the local gun show, I bought a no-name flat top upper - Cherokee, 2012-10-03, 16:13
 - ..Yr' pref's? -- keep 'em coming. On the right track, thanks - John Meeker, 2012-10-03, 21:16
 - LW-upper configs for AR .. doing due diligence. will report - John Meeker, 2012-10-04, 08:52
 - It's not called an M4gery for nothing - 
Miles Fortis, 
2012-10-04, 17:36
- SBR, etc... - 
Slow Hand, 
2012-10-05, 04:02
- get a 'flat top' rail upper - Miles Fortis, 2012-10-05, 16:37
 
 
 - SBR, etc... - 
Slow Hand, 
2012-10-05, 04:02
 - Been looking at LW-upper configs for AR ...Yr' pref's? - 
Warhawk, 
2012-10-05, 14:40
- Been looking at LW-upper configs for AR ...Yr' pref's? - Warhawk, 2012-10-06, 20:07