Hello,
I remember that many years ago Leica made a small special series of M-type lenses for screw mount, e.g.the 1:1.4/50 Summilux. There was only a small number and they were very expensive. In the early day of the M-Leica some lenses were sold with a glued on adapter on the thread. It was said that it was nearly impoosible to loosen the glue (maybe a two component epoxy). The difference in register between M and screw mount lenses is exactly 1 mm.
I remember that many years ago Leica made a small special series of M-type lenses for screw mount, e.g.the 1:1.4/50 Summilux. There was only a small number and they were very expensive. In the early day of the M-Leica some lenses were sold with a glued on adapter on the thread. It was said that it was nearly impoosible to loosen the glue (maybe a two component epoxy). The difference in register between M and screw mount lenses is exactly 1 mm.