Originally Posted by Cnynrat
I am working on building my first AR15 upper. I have a CMMG upper and will be mounting a Daniel Defense Lite rail on it. The Daniel Defense barrel nut does not thread onto the upper easily by hand. It goes on easily for the first 3-4 threads, and then gets pretty tight. I can't get it on any further by hand. I don't have the proprietary DD wrench yet, so I'm not sure how far it would go on with the help of a wrench. I should have the wrench in the next few days.
This is without the rail or barrel in place - just test fitting the nut by itself. Threads on the upper and the nut look fine. I am wondering if this is normal, or perhaps did the anodizing on the upper go on a little thick?
Can you give it a try BACKWARDS? If it won't thread at all, that would tell me it's probably designed to lock on when installed, preventing loosening of the nut during use. From what you wrote, it sounds like a design feature and not a bug.
Good luck with it! Keep us up to date! Might add pictures as well for future reference by others!