Originally Posted by jlland70
Been reading good reviews on the carbon fiber receivers... But my brain still equates "carbon fiber" with "plastic"
Actually, Carbon 15's are not carbon fiber. They just use carbon in the model number as a trade name. Plastic is closer to what they use. Not saying it is bad. If as many have failed as the posters here claimed, the line would have been discontinued long time ago. Still, I feel more comfortable with aluminum. The barrel is the heaviest part of the upper anyway. I would personally go with an aluminum upper, and if you are looking to make a lite weight AR, get a lighter barrel.