I used to be able to hit 8 ring on 100yd NRA paper with my FAL at 500yds. Had a cheapy BSA 3x12x50mm. A bit foggy but it did the job. I'd be lucky to even hit the paper at 500 now... I'm so outta practice. I agree with you 7.62x51 aka .308 is an awesome all around cartridge.
**warning: military (usmc) bragging in this post**
we had to hit a man sized silhouette target at 500yds w/out a scope in the marines....i never really figured out why; i mean, at that range your windage/elevation has to be perfect and when in combat are you going to take the time to change you dope to make a 500yd shot through iron sights? oh well, it was fun calling "head or nuts" from 500yds out and actually making the shot
**ok...branch of service bragging over...continue with normal conversation**