I was ordered a Cowboys jersey for Christmas (it was backordered so it isn't here yet), and it is size "52" which on the Cowboys store website lists it as XL but most other clothes I looked up call a 52 chest a XXL. I would rather it be too big than too small and I have never really had a jersey to compare it to. I'm kind of an average sized dude 5'11 and like 200 pounds. I figure they probably run big since they are supposedly authentic and meant to have pads on and stuff right? They make a big deal about "no changes to orders" on the website.