Raphaelargus on page 107 did a comparison of Rancourt, OSB, and Quoddy's moc shoe sizing. From his comparison, Rancourt and OSB's length is pretty much the same, with Rancourt being a teeny bit longer. But the biggest difference is the width. Rancourt's is more tight compared to OSB's moc in the toe box to vamp. I have OSB trail oxford in size 7D and rancourt in size 7D (left shoe). I agree with what he said about the width. I found OSB to be roomy in width but rancourt's shoe was more tight all around. I didn't really notice much about the length though because of the width difference. It might be that D width from OSB would be roughly like a E width from Rancourts.