I can't figure European sizes. I wear a 32X32 pant and usually a large shirt, I'm not a big guy but whenever I bought Euro clothes, the shoulders were too tight, or the sleeves were so short I couldn't get my arms through.
I bought an "Extra Large" Dutch utility shirt from U.S. Cavalry figuring the extra large would give me room to move. No way, I couldn't even get the shirt to button up it was so tight.
Same thing when I bought a German "Snorkel Parka" in extra large, the shoulders were so narrow I couldn't put it on.
I did find 2 British DPM shirts at my local Army/Navy that fit. The only 2 in the whole store, so I bought them both.
Now I steer clear of surplus cloths, especially mail order stuff. They give the clothes their own sizes so who knows what size you're really getting.