Watch out for carbon fiber wrapped barrels. They insulate the heat from escaping to the surface to cool. So it may feel cool to the touch, but in reality it's red hot in there. Just an fyi.
I you don't believe me just start researching Christian Arms carbon barrel fiasco.....
To be fair Christenson has problems building AR15's with any degree of success, the fact that they can't do CF barrels doesn't mean CF barrels can't be done. They lack competence, but not (over) confidence, and have no problems (over) charging their clients to finance their learning curve.