[marknorton]

I agree, the Summicron is out of adjustment. Did I understand you correctly that you had some of the lens elements replaced? If so, they may not be seated properly. Otherwise, it's possible that the lens is focussing beyond infinity, meaning that when you set the lens to infinity, it is actually too close to the focal plane and then nothing is in focus, anywhere.

You might try backing the lens off from the infinity setting by small amounts to see if the focus improves. This is exactly the problem I had with my Noctilux - set to infinity, nothing in focus.

In a test like this, it's worth avoiding using the rangefinder and just bracket focussing. As soon as you bring the rangefinder into the equation, that's one more thing which might be out of adjustment to complicate the test. The Summilux is working well though.

[BTW, handy infinity reference for you to have available with lots of detail to check on the spire and edges against the sky to show up any fringing...]