I can easily hit, with iron sights, a target out to 500 yrds.
A scope makes it easier, faster and increases distance....
At one point, during my competition shooting days (1978), I shot a record 34 consecutive V-Ring bullseyes at 600 meters, firing a match M-14 with iron sights.
As far as I know, nobody has broken my record.
Said with all humility, of course…