I don't have any Experience with their take downs but after you solve the head spacing nut problem don't give up until you have tried the gun with multiple different shells.
I have sighted in probably 20+ different 22's and I refuse to use match ammo for plinkers. I have been amazed at what a change of ammo does to the groups a 22 will shoot and I have been shocked at some of the ammo that shot very well in certain guns when most others didn't like it.
If you take a bag of 10-15 different boxes of ammo and your gun is a picky one most likely it will like the one you have the least of or is the most expensive!