I am currently building carbon fiber sleeved barrels. The ones done by Christiansen Arms are wrapped with carbon fiber after turning down most of the barrel to a fairly small diameter. I'm utilizing a sleeve of rigid tubing with internal de resonators. Either way, the concept is that the barrel is very stiff but not very heavy. Also, carbon fiber disperses heat very well and isquite stable over a wide variety of temperatures. The material is very strong and I have not had any issues so far with rough use. Its best application seems to be varmint rifles - although I have done a few for police snipers. Most folks consider it an alternative to barrel fluting.