ssCoyote
I use the B&D 3.6v power screwdrivers with the sinclair case holders and zero wobble since I switched to them.
Assume you are resizing case and then expanding necks first with the matching neck expanding mandrel that goes with that specific mftr neck turner. If not that is first problem.
Lube inside of necks and outside, FP-10, imperial size die, auto assembly lub are good choices and Sinclair sells all 3.
Do not try and take all off on one cut. Take down to leave about .001 for final cut after having done all down to that point.
You can kind of force the cutter on pass down and it will leave ridges on neck, slowly back turner back up the neck and should be smooth with zero ridges.
Finally, cutter should be sharp, if not it will wobble and drag so replace.
What kind of turner are you using?
BH