I don't have the heavy barrel version -just the "standard" which is pretty stout for a rimfire barrel as is, and the hardwood stock. Mine is a 1/2" (or less) grouper at 50 yards with a bunch of different ammo. It is scoped with a 4-12 X A.O. Bushnell in Weaver rings attached via Weaver bases. The point of impact varies with some of that ammo but it groups just about everything well. In point of fact, mine is the most accurate "sporter weight" .22LR rifle that I've ever shot, and I've shot some of Dieter Anschutz's finest. I've never shot an Anschutz sporter that grouped better than my XT-22 will. I haven't had a failure to feed, eject, or fire that wasn't ammo related, and that was with a batch of 20 year old Remington ammo that wasn't so hot in my 10/22 when I bought the stuff way back when.
Question for the OP: Did your bore have some brownish, thick, industrial strength preservative goop in it? Mine did, and that stuff was a bear to get out!! I can't imagine how it would have shot good if I'd have left any of it in there. I recently bought a "New In the Box" Remington 721 centerfire rifle that had this same kind stuff in it that was even harder to get out after 60 years of time to soldify into a waxy mess.
I absolutely love my XT-22. It is the best new firearms purchase that I've made in over two decades.