Yes, I'm in the process of reading through this thread more thoroughly and it seems most people are recommending to size down for the Bedale. My true chest measurement is 43" and my normal suit jacket size is 44, though I can wear a 42 in some cuts. As I'm in between sizes, this makes the decision on Barbour sizing all the more difficult. Unfortunately I am not near a store where I can try one on. I ordered the a 42 Bedale, so technically that's sizing down 1 inch from my actual chest measurement, but you say you went all the way down to a 38?! Wow. Do you mind sharing your actual chest measurement, height, and weight? I'm 5'10", 185 pounds, athletic build. As I mentioned in a previous post, I don't plan on wearing a lot of heavy layers under my Bedale since I'm in Texas and likely wouldn't need it. I'm envisioning just wearing a buttondown shirt under the jacket, maybe with a sweater at most, but often with just a t-shirt underneath. So I'm thinking maybe I could size down to the 40. I'd also like to drop a few vanity pounds down to around 180, but I doubt that would have much effect on my chest size.
Then, there's this detailed guide someone posted earlier in the thread, which says to buy the same size Barbour as your actual chest measurement. As much as I love shopping online, sometimes I hate it.
I think you could size down to 40 since you are not going to wear a lot underneath. Give us an update when you receive the jacket. I'm 6'1, 180, bedale size 40