Ummmm - - -Isn't the Taurus 66 a six-shooter?
Pretty sure it is. My brother has one and I gave him a couple of HKS speedloaders for K-Frame S&W and they worked just fine. It is marked "10" on the twisty-knob.
Later edit: Though I admit that the chart linked above sure confirms what you wrote - - -;p
Best,
Johnny Guest