I have the one Black Dog that came with mine and three CMMG mags - they all work the same way in my 522 - no failures.
I can't really tell you about accuracy, I have a red dot on mine and the best I can manage is about a 8" pattern at 100 yards from a mag full.
They are making a new bull barrel for them that I badly want to get my hands on, I believe it is included with all newly manufactured 522's. If I can manage that I'll probably put a scope on it.
I would also say that the trigger is very similar to my 556 in case you've felt one of those before.
I can't really tell you about accuracy, I have a red dot on mine and the best I can manage is about a 8" pattern at 100 yards from a mag full.
They are making a new bull barrel for them that I badly want to get my hands on, I believe it is included with all newly manufactured 522's. If I can manage that I'll probably put a scope on it.
I would also say that the trigger is very similar to my 556 in case you've felt one of those before.