-There will be no ring around the front carbon. The ring would dent/fail before the carbon would.
-There is already a rear metal enclosure, it’s integrated into the clamp by design and acts as a backstop when sliding the handguard over the clamp.
-No it won’t fray, this isn’t made like chinese carbon products with inferior resins and weaker vacuum forming process. You’ll dent an aluminum handguard far sooner than cracking this carbon one under equal pressure abuse. When I pulled the first prototype out of the mold I did an offhand test by throwing it into the concrete floor of the shop as hard as I could. It didn’t even crack then.
Go try that with an aluminum handguard and let me know how it looks after 
Thanks for the comments folks!