small correction, i have a 1200A, not 1500A, shunt. not that it's gonna matter anyhow.
it had stamp of 50mV and i was thinking it was good for input to ic but it reads .4 ohm so i don't believe i will be using it.
the 200A is stamped 75mV with .3 ohm on DMM. fat chance to use that also.
You mean 120A probably.
A 120A shunt for 50mV full range reading has R=0.0004 ohm
A 200A shunt stamped 75mV has R=0.000375 ohm
You cannot measure resistance of those shunts with your DMM that way, I am afraid..