No: there was no particularly visible gap but during the rusting process of rebrowning them, I pour hot or boiling water over them. The bubbles were quite noticeable then. During the rusting phase, you can get a dark strip along the rib where it is not rusting properly because of oil migrating out of the crevice. I have had similar indicators (oil smears) on damascus rifle barrels when the rib is partially loose.
Most of the rust on this gun appears to be from the bottom of the rib and strangely there is very little pitting for the amount of rust.
cheers Doug
