M14 EBR firing LaRue and Engel Ballistic Research 7.62x51mm subsonic at Silencertests Shoot 2009.
Order yours here:
Engel Ballistic Research 7.62 Thumper
I've sure seen a lot of nice suppressed M1As and AR-10s at our county ranges, and they'll shoot way out past 500 yards with these rounds.
I’ll admit I was wrong. I had no idea anyone manufactured sub-sonic 7.62 x 51mm ammo.