let me explain
What I should have asked is "how light can a AR get?"
I looked at the Carbon 15 on bushmasters page and saw 5.5 lbs. but never had one on a scale.
I used a GWACS lower(polymer) and a 16 inch "pencil style" barrel and I am just under 6 lbs.
A 11 inch barrel with a 5.5 flash suppressor might be lighter and a polymer upper may shave a few ounces.
I also have mid-length hand guards, carbine would be lighter.
What I would like to know is how much do these things take off the weight.