One of the pics Gary (Geedee) posted recently, possibly in the 'Mustang' thread, shows the apparent 'stagger' of the guns in the P-51B/C wing to good advantage. The two guns per wing were angled over, in order to fit into the wing, a method which caused feed problems under certain 'g' conditions. This was partially alleviated by fitting step motors, from B-26 waist guns, but not completely cured, until the 'D' model, and the vertically mounted three guns per wing.