By all means, I am not here to ruffle any feathers but, I did give an honest try at 100 yard 22LR shooting just before I left Alberta.
Using an okay rifle (ES350B Mauser single shot .22) and a good scope (Weaver T-10) a very good friend of mine, (Silverback) punched an awesome 3/4 inch group, with proven ammo. (PMC Moderators) Of course no wind, off the bench.
This kind of performance, is not easy by ANY means.
And as we all know, there are far better, target rifles out there.
Most rifles that are capable of this, or better, are not semi-automatic rifles.
Maybe Ski911's rifle is heavily (read expensively!) moded?