LMT (Lewis Machine & Tool) have developed an AR-10 version of their AR-15 CQB MRP rifle called the MTP MRP 308.
Click to expand. Photo Copyright Ken Lunde. Used with permission.
It uses the LMT Monolithic Rail Platform which is a one piece upper receiver and free floating handguard that is machined from sold aluminum.
The AR-15 MRP upper. Click to expand.
The name suggests it can handle the higher pressure .308 Winchester round as well as 7.62x51mm NATO (no, they are not the same).
I don’t have anymore info on the rifle and do not know if it uses the LMT gas piston system.