I've used a Pentax screw mount 24mm WA on a screw mount Leica with a home-built dapter which mated to the two different threads and provided the required registration distance. No focus coupling, of course, but not much of a problem with a 24mm lens and my estimation of subject distance.
The combination fuctioned well but the particular SLR lens I had was very bulky on a Leica IIIf.
Presumably, I could fit the lens to an M Leica with a screw to bayonet adaptor.
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