First, I'm not a sifu... just another user sharing my humble opinion. I don't see any good reason why you want to use your Leica R lens on a M body.
If you have R lenses lying around and want to make full use of them, then get an adaptor and use it on say, a canon dslr, or for that matter, a R to M43 or R to nex adaptor for use on MicroFourThird, nex bodies respectively.
When its not rangefinder coupled, you can still use on a M body via an adaptor but you can't "focus" through the viewfinder using the split-image / alignment method. Stopping down and shooting it using hyperfocal / scale focusing is OK but then, I see no point in doing this...
** MDa is just a reference that's all