I do not have a 308 S&W nor the Ruger SR762, my 308 is a Seekins Precision and my 5.56 is a Ruger.
Like the SR762, my Ruger is a piston driven rifle. I love it. It's SO much easier to clean. I've cleaned a many DI rifles, so the piston thing carried a lot of weight in my decision on the 5.56. It will shoot 7/8-1.25" groups. Maybe that's important to you maybe not. I wish my Seekins was a piston rifle.
It took me a year and a half to decide on my 308.... painful.
Best of luck
Bob