How waterproof/weather sealed in a leica M?

[damonsong]

I have been wondering about this for a long time, at least now I know I dont have to worry too much to take my leica out in bad weather, but what about the Lens? are they rain-proof tho?

 

[Vickko]

I recall the KE-7A was reported as water-tight, not water proof. There was a rubber ring under the shutter dial which made it very stiff, and I recall that the top cover was sealed on with wax. But the rewind knob and advance lever slots didn't look any better sealed than an ordinary M. Plastic bag is your best bet.