I want to say that you can shoot outstanding groups at distance with irons. But it takes practice. And it takes a large aiming point.
This is one version of the 5V, to be used at 500 yards. If you have ever seen a M1903 front sight, this target was made so you could place the M1903 front sight at 6 OC on the thing. With young eyes, it looks like a round pin head at distance. Incidentally, this is the basis for those "NM" M14 and Garand sights. I tried a wide combat Garand and M14 front on this target, at 500 yards, and found it extremely difficult to place the pin head in the middle of the front sight. The appearance was closer to a speck of dust that disappeared as the wide blade approached it.
The top target was the old 500 yard NRA target, and even though it is wider, I hated it. Too small. The 600 yard target had the same ring size, but the seven ring was black, and that made it much easier to see.
I regularly pulled targets with shooters who shot 198's, 199's on the NRA target, and I cleaned it once with a M1a at 500 yards. The ten ring is twelve inches at that distance.
I am sad that the discipline of iron sights is going away. All the good scope shooters I know were good iron sight shooters. Irons require that you take the exact same stock weld each time, center the post exactly, and that forces a shooter to have a consistent aim point. You also see how the group moved up and down, based where your face is on the stock, and left and right, as the stock moves in the shoulder.
One of the things about scopes, that I do think is bad, is that it encourages shots at distances were the shooter has no reasonable chance of hitting a pie panned sized lethal zone. I see at the range rifles with huge scopes, on clear days you can see the moon! But shoot at the moon, you are not going to hit anything. At least with irons, the engagement distance is limited by target size. If what you are aiming at is too small to provide an aiming point, that is a clue that maybe you should not be taking that shot.