Blake,

I don't have references right at hand, but IIRC the textbook for the class I took a few years back Mountaineering: The Freedom of the Hills listed sighting compasses like the Silva Ranger as having a degree of accuracy of +/- two degrees.

Of course, it's not just the compass itself but how it is read. A baseplate compass (without sighting mirror) might be just as accurate, but how do you accurately take the sighting? The mechanics of sighting and then reading the sighting will make a reading from a baseplate compass generally less accurate than from a sighting compass.

And of course, there's no substitute for training, experience, and practice. Having an accurate compass that you don't know how to use correctly pays no dividend.

HJ