EFFECTIVE RANGE??
As in guaranteed hits on a torso sized target?
What position ....
shaking with adrenalin and fatigue after assaulting up a hill??
Or cool and calm, on a bench at the range??
With IRON SIGHTS, in DIM LIGHT??
OR ...
With a clear high powered scope with built in reticle that does the ballistic dope for you??
Worst case scenario in the real world ...
not very long at all.
EG: I once missed a shot at a home intruder inside my bedroom.
Best case scenario ...
as far as the target can be seen and properly identified as a valid shootable. With any good .308 Win/ 7.62 NATO rifle, that can be over 1000 yds.
Personally, in the real world, not just on the internet chat groups where mile long one shot kills seem to be the norm, I wss once a competitor in the DCRA matches, which went to 1000 yds. I was never that good, but I witnessed some incredibly shooting at 1000 yds, with IRON SIGHTS, MILITARY ISSUE 7.62 NATO AMMO ( standard issue ... not "match grade"), and DCRA converted to 7.62, #4 ☆ Lee Enfield "antique" rifles.
Any one who stood up at 1000.yds in front of these guys was a goner.