For irons I'd call that a good group and adjust them accordingly. What distance do you intend to zero the gun for? If it is under 75 yds. or so, do you really need a scope for that distance?
For whatever reason, 100 yards is the target.
It's the distances beyond that where the scope might come in really handy.
If you could see the sights AND the target I'd be happier.
I like to get my groups under a