Bringing this one back to the top. Look at the photo on p. 1, showing the open action. I asked the question before, and it still bothers me. I've seen guns with both square and round crossbolts. However, the one in the photo has what appears to be a square crossbolt paired with a round hole in the rib extension (like for a standard Greener round bolt). How does that work? All the square crossbolts I've seen before mated with square holes in the rib extension.