The problem is he is looking for 1/2 MOA, not 1 MOA. He's shooting an ARA target, which at 50 yards requires just over 1/2 MOA to clean the card.
As for POI changes from bull to bull, it really depends on your setup. Using cheap bags and rest with no consistency or concern for rifle handling, POI can be all over the place, at least relative to the size of the ARA target. Get good rest that can do both windage and the fine elevation changes along with a quality rear bag, not near the issue. Rimfire competitions often allow one piece rests. You can spend as much on a rest as you can a top end rifle. To shoot consistently great scores is expensive, even if you are using Wolf. On the other hand, grabbing a Caldwell Rock BR and a Protector rear bag will get you on the line around $200 and should work well enough for all but the most serious shooters. It really depends how far you want to go.
As for POI changes from bull to bull, it really depends on your setup. Using cheap bags and rest with no consistency or concern for rifle handling, POI can be all over the place, at least relative to the size of the ARA target. Get good rest that can do both windage and the fine elevation changes along with a quality rear bag, not near the issue. Rimfire competitions often allow one piece rests. You can spend as much on a rest as you can a top end rifle. To shoot consistently great scores is expensive, even if you are using Wolf. On the other hand, grabbing a Caldwell Rock BR and a Protector rear bag will get you on the line around $200 and should work well enough for all but the most serious shooters. It really depends how far you want to go.