Carbon fiber pistol grips

I've never seen one and doubt I ever will. CF is laminated not molded. It's probably possible but you wouldn't want to pay for it! I doubt the weight savings would amount to much if any. Parts that don't weigh much to start with are difficult to make lighter. My ultralight build will wear a BCM Mod 0 with the door and hardware chopped off. Not much lighter but a few 10th's of an ounce for nothing! GH
 
While I have said many times that ounces on any AR quickly add up to pounds...you won't really find a huge variance in grip weights (aside from comparing large grips with palm shelves, heavy overmolding, etc. to something like a basic A2). You'll be far better served to look for weight savings elsewhere on a part that isn't, more or less, already as skinny as skinny gets. ;)
 
I measure Every thing. The plastic AR15/AR10 pistol grips weigh 2.35 ounces. A Hogue soft pistol grip weighs 2.70 ounces, and the Ergo with palm grip weighs 5.40 ounces.