I hope you all understand that I am not trying to **** any of you off. But there are differences between .308 and 7.62 x 51 the NATO cartridge is made a little longer and the brass is a little thicker. That being said, in my own mind I believe that there are really nothing to worry about. Having said that I am looking for really expert information, not just what you believe. Again I believe that both are compatible, if you read the article I put here, it basically states the chamber pressures are the same. The most improbable impact would be case length in my mind that might cause problems. My reference to the ruger site was that ruger absolutely states that either 5.56 or .223 can be shot in any ranch 14 with the exception of the target model. I would love it if Springfield had the same thing only for the M1A for .308 and 7.62 x 51.