Just remember, as hinted at in the post above, there is no single standard .308/7.62 AR, like there is for .223/5.56 rifles. There are several incompatible, competing platforms. The AR10 you mentioned is only a product of Armalite. It's incompatible with the RRA and DPMS .308 models.
The majority of 7.62 ARs use the KAC/DPMS pattern, and those that take the Armalite pattern are all built on Armalite receivers (Aero, Noveske).
REPR, OBR/Predatar, MA-TEN, PWS MK2, SR25, Colt 901, Sig 517, CMMG, Bushy, and MWS all use KAC/DPMS pattern.
See this link for a compatibility chart
The HK 417, SCAR 17s, and the rest of the legacy battle rifles (G3, FAL, M14, etc...) use proprietary format.