Well I purchased the XL jacket after trying on the Medium and it being a little snug. The funny thing is the XL with both liners fit perfect so I'm guessing they dont have to big a difference in the sizes. With Both the liners out of the jacket it still fits nice and the sleeves have snap adjustments on the elbows to keep the armor in place. When I have both the liners out I snap those on the inside button (there are 3 buttons) and with each liner I snap it out 1 button so the arms always fit and the elbow pads stay on my elbows. The rest of the jacket seems to always fit with or without the liners I cant tell much of a difference.
I also dont like things to tight so its not a custom leather feel but more like a tailored suit jacket fit. I wear a 36-38 in pants and a XL T-shirt (46-48) mostly the XL T cause like I said skin tight isnt really my thing.
So with a standard tape measure meaning not the most accurate...
Arms (from neck/shoulder line down outside arm to wrist) 28 inches
Back (neck/top of shoulder blades down back) 23 inches
Chest (under armpits) 41 inches and an A cup lol j/k
Beer Belly (around love handles) 42 inches
I would say that if I had a bigger belly and both liners in I would want one size up on the jacket. Anyhow hope this helps I think this jacket is definately the way to go for the money.
Pauly™
P.S. This topic has a pic of me and my jacket
http://forums.banditalley.net/viewtopic.php?t=7&start=525