So, I finally got my parts, I was assured that I needed the Howitzer 73mm shell with a 56mm chainline. However, this sets my cranks cm's (yes plural) away from the frame. Question is, those of you who have Socom's (if any), if you built it with a Howitzer, what size did you use? I'm gonna try the 51mm chainline tomorrow, but it looked to me like I needed to loose more than 5mm on either side.