Does anyone know why it’s not accurate? What about the design? Is it the bolt?
Having avoided them like the plague, I'm going to regurgitate the generalized complaints of owners...so please take this as only an educated opinion:
Thin barrels that had more pressure applied at the gas block than other designs (eg. ARs). Add a wood or plastic stock that isn't precisely fitted, and you have multiple contact points that really screw with the harmonics of any barrel - let alone a pencil barrel...especially a wood stock that expands and contracts with the environment.
I *heard* the older barrels were button rifled poorly, and had a lot of stress relief that caused POI shift once they heated up. I guess their CHF process helped alleviate some of the problem, and this is why they are regarded as 2-4 MOA rifles now as opposed to minute of pie plate. Again, I have no experience here.
Top it off with crappy iron sights and a trigger that wasn't great (I have fired a couple rounds through one), and you have a recipe for disappointment if you are expecting long range varmint accuracy.
But the rifles weren't designed for that purpose though.
Just my .02.