One 50Mv 500A shunt, two ammeters?

MrWizard wrote:
That's not the problem
75mv shunt and meter are common
The current meter and shunt are 50mv, and he can't find another 50mv meter to put on the circuit

There is no difference between a 75 mV 750A meter and a 50mv 500A meter and shunt when you're measuring less than 500A current. You have a meter that reads 10A when it sees a 1 mV input voltage, and a 0.0001 ohm shunt. If the 75 mV standard ones are easier to find, there's no reason not to buy one and use it with the 50 mV shunt.

(There would be a difference in the maximum power rating of the two associated shunts: the 500A 50mV shunt dissipates 25W maximum, while the 750A 75mV shunt needs to dissipate a little over 55W at its full rated current.)