I have owned a G3. Got rid of it as soon as I could. Horrible excuse for a rifle. For semi-auto 308, the M1A rules, second choice FAL
The rifle operated perfectly. It just does not "feel" like a rifle, harsh recoil because of the operating system, hard on brass, heavy and poorly balanced, no way to use a riflemans sling. I just did not like it. I know a lot of people like it, I just don't.
I think AR 10's are slightly more accurate, but M1A's are better for SHTF.