The Larue PredatAR has a free floating lightweight barrel in a proprietary upper with free floating hand guard.

The barrel is made in house, the barrel nut is 1 1/4 inch.  The heat treating method that Larue Tactical uses gives it a golden, almost brass like color.

The upper and rail have mating surfaces to ensure alignment.  4 screws hold the rail to the  upper, with helicoil(or similar) inserts.

So, why did I have this one apart?  I was showing it to a friend expounding on how great Larue stuff is.  When I got home, I was looking it over again and I noticed a very small amount in play  in the barrel.  After removing the hand guards I found the barrel nut was loose.

Now, even more annoying is that I don’t have a wrench in 1 1/4 inch size, I visited several local auto parts stores and hard ware stores and the half dozen stores I visited this weekend didn’t have a crowfoot wrench in that size.

Goes to show that no matter what your equipment, you need to inspect it regularly and have spare or backups.