I guess so long as the curveture of all the bullet noses are the same, it doesn't matter what diameter they are... But that is a big ask and I doubt they are. Although if they are very close (which I'd say they would), the actual difference in length you're measuring will be very small indeed - like less than calipers could measure I would have thought? You know, sine rule etc..
Basically I would have thought, so long as you use the same comparitor, and only using it for comparing to a reference (or a few) dummy round it'll be close enough even for match shooting, let alone hunting. But I guess it's even debatable you really need it for hunting at all.