The reason Parker, L C Smith, Lefever & others have a joint in the top rib has nothing to do with expansion. As these guns have rib extensions with top fasteners the rear section of the rib is brazed along with the joining of the barrels & under lump. The rest of the top rib along with the lower rib is soft soldered.


Miller/TN
I Didn't Say Everything I Said, Yogi Berra