I apologize for the confusion. I am new to the forum and got excited when I saw that I could try and help someone. As I found out when doing my handguard on my AR556 any handguard will fit you may just have to put a mil-spec barrel nut on or the proprietary one for that brand. As far as the original barrel nut and fit of handguards I'm not completely sure. Again, I apologize for any confusion.
JW, you didn't confuse me, or, anyone else that I am aware of. I'm sure you might have helped someone out there in the AR world.
I knew how to install a drop in hand guard on my AR-556, but, a friend suggested that I watch a video on YT about installing an MAGPUL MOE SL hand guard onto my AR-556.. He stated that it was tricky and the video would help with the install. And, he was correct! (Thanks Charlie :Cooltu: )
Here is a pic of my AR-556 with a MAGPUL MOE stock and MOE SL hand guard installed.