I bought a small regular - Propper TAC U Combat Shirt w/ External Elbow Pad Openings

So sizing on this is so confusing on the charts I have seen on the web, I have even seen conflicting charts, even a chat with the Propper people was totally worthless. So, I rolled the dice. Here is why I chose a small regular:

I am 5' 10 (70" for those that can do math) and crazy striated. I weight 150 pounds, maybe 147.5 depending on hydration level. My sleeves are 22.5" and my chest is 37.5" (not puffed out, just standing there). So, I am right on the cusp for small and medium and I went with small regular and it fits awesome. Perfect. The chest and back material is stretchy so you have some give - though it is not tight on me. The arms are plenty long when out in front or over my head and short does not rise up on me when I do burpees. And the torso length is long enough to tuck in IF I want to, but not laughably long like a thug. Small regular was the best choice as medium would have been to loose and baggy on me. Small regular will not have extra baggy material flappin in the wind, it is a svelte fit like I am, and that is how I like to wear my clothes and gear. No loose fit for me. This size is fine for me with a t-shirt, synthetic of course, under it or maybe a nice synthetic tank. Not much more than that. I look so tactical in this shirt it is scary. I showed my wife, she nearly fainted. Design is fantastic with pockets in all of the right places - I have places for knives, gels, tactical flashlights, throwing stars, a cell phone for selfies, extra magazines, chapstick, light sticks, you name it. Quality seems real high - better than expected and that is no joke - really well thought out design and I looked at all of the top tactical shirts before buying. Even velcro patches for your neat USA flag you will feel obliged to buy and stick on. The ninja hands will be nice on chilly days. Color of Khaki is not as FDE (for true operators out there than know FDE) as I had hoped or some pictures show, it is a much lighter khaki. I plan to use some closed cell foam from an old sleeping bag ground pad to make some elbow pads since there are pockets for them. FWIW I bought elsewhere online, not Amazon. If I can dig on it, and I am picky about tact gear, you will dig on it.
Pros: great fit, great design, tons of bells and whistles
Cons: hard to nail down sizing, khaki is lighter than expected

This review was written in the old system and had content requirements that are different than reviews written today.