Yup, BOS min connect for domestic to domestic is 40 min normally, however for some reason BGR has an exception:
DL-DL DD .25 ALL - BGR
DL-DL DD .25 BGR - ALL

As mentioned above its pretty easy to get from one end of the airport to the other in 10 min, however you also have to include getting off the plane from your inbound flight. Unfortunately both flights can be in either side of the terminal so you won't know until day of departure. Delta used to have some handy 'walk time' info in the sky magazine back when it was in the seat pockets, in the airport maps section to show max or typical walk times between example gates at a bunch of airport. I don't see that info on their website unfortunately.