I would really like to see how they dealt with this problem in a mortise cylinder as well. Unlike the Corbin master ring, the Sargent master ring has the plug offset in the ring. I just couldn't picture this working properly. When the plug rotates, the action is typical of any regular cylinder, but rotation at the master ring causes the plug and tailpiece to rotate in a sweeping motion, almost like the piston connections on a crankshaft. After taking apart the cylinder used in the Union Lock, it became apparent that there is enough play built into the tailpiece driver so that rotation of the master ring still rotates the locking mechanism. However, I can't imagine how such a cylinder would work in a typical surface mount rim lock unless the tailpiece was mounted to the back of the core along a large sliding groove? Was it possibly the limited uses of this cylinder that led to it disappearing?