I have R2A, and never was able to get completelly "focused" image focusing at infinity (that is, when focused to infinity, and looking at very distant object through viewfinder, there is double picture in "yellow spot" in viewfinder, never images combined in one sharp image). But, when focused on near(er) object, there are no those problems and focusing allways is acurate. And it happens with mine both 35mmPII and 75mm lenses.

That is short rangefinder base problem I was told.