Carbon fiber dust is not good to breath. When you have buffers springs and shell rims running against the unfinished fibers, it will abrade and create dust. Those particles are like miniature barbs in the lungs. Also a big reason we do not put slots in our hand guards...not good in the skin either.
Believe me, I looked at CF buffer tubes and magazine extensions...took very little to realize it was not a good idea.
I'll probably get more hate mail again, but one thing I take seriously is undue risk.
The combustion gases are not good either, never had that in any designs we sold, just tested it.
I've read marks post about the carbon fiber dust before. He know a lot more about it then I, but I have taken his advice to heart. There is nothing in this sport worth killing my self for.
Your body can't break down carbon fiber. Once it is in you, it is not coming out and just keep get deeper in your lungs and it can create some nasty health problems.
I hope this dose not come a cross wrong but just trying to look out for a fellow shooter.