sinclair sells a power motor tool that you turn your cases on and handhold the turner. You can also use it to do primer pockets and inside outside bevel brass after trimming.
the sinclair motor uses their power case holder adapters and it really works smooth. I have on older model made by one of their employees that has fwd and rev. I use it for neck turning and I have the newer model for the pockets and other stuff.
Pic #1 is the old sinclair motor that used to be made by one of their employees.
Pic #2 is the current sinclair motor sold by them
Pic #3 is the Joel Pendegraf K&M neck turner holder ($40) works great and makes holding the tool easy. you can PM him at BR central if you want
Click on pics to enlarge.