I'm sure Uncleknick can do the spreadsheet graphing, but it looks like #8 is promising. A darn near straight line between 7 and 9 with small vertical rise. Although the line goes 7 9 8 from bottom left to top right it seems like those shots might be close to a harmonic node.
Not enough data to know for sure, but that is where I'd start.
Machine guns are awesome until you have to carry one.