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 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.