There's a little confusion running through this thread
This is because there's two simple ways of looking at how a shunt works:
1) The meter works as a voltmeter, and measures the voltage dropped across the shunt.
2) The meter works as a micro(or milli)-ammeter, with most of the current bypassed through the shunt.
Both are really the same thing.
Essentially all meters were micro/milli-ammeters - to make it into an ammeter you put it across a shunt, to make it in to a voltmeter you add a series resistor.
As you're not adding a series resistor in an ammeter you're not 'specifically' measuring the voltage.
However, it's common practice to add a swamp resistor in series with the micro/milli-ammeter - this isn't particularly to make it read voltage, it's to 'swamp' the movements own internal resistance, because different meters have different internal resistances. By adding the swamp resistor a meter manufacturer can compensate for different movements, or different values even within the same model.
There are also high current meters that work directly (no shunt), the movement is just wound with VERY thick wire
old car ammeters are a prime example.