i have a spec from a client which list 2 materials, ASTM A320 L7M and ASTM A320 L7S. i can find a spec for ASTM A320 L7M and ASTM A320 L7 but i can find absolutly nothing on ASTM A320 L7S. dose it exist or could it be that it is the same thing as ASTM A320 L7.