I have been wearing 2XL part number 72158 and was looking for couple more.
I love this shirt. Feels good, well structured. I ordered a L which is my normal shirt size. While the shirt fits well, the only issue I have with it is that if I flex/move too much, the snaps on the front of the shirt come undone. Buttons in my opinion would be much better.... or a better quality snap. I like the shirt, but the snap issue made me drop the rating.
I wear a 44L jacket and the extra large fit well. The shirt is comfortable and doesn't chaff. Movement in the shirt is free and doesn't bind. The best asset of the shirt for me is the gussets on the sides of the shirt tail. I CCW under the belt in back, and the shirt design not only covers well, it pulls out of the way very quick and easy for weapon access. I just ordered two more shirts. The only draw back for me is the lack of color choice. Only one color available in xl at this time. Overall a good value for the sale price.