Direct impingement vs piston system. Are the 7.62x39 ARs chrome-lined?
Isn't everyone?
I'm revisiting the shooting in my head, and wondering if I didn't throw my first round of groups using the factory folder with a poor cheek-weld. Not impossible.
Remember, these are statistical averages, not one offs. So I had some groups with the Polish surplus that were under 2MOA. But if I just chose the best groups of each, that's not very representative of how I shot as a whole.
I guess we'll find out if other people start producing better groups when they get their rifles!