Re: For those of you that use a NECO concentricity gauge or similar style...
You can't fix runout by bending necks, and it's a bad idea to do this IMO.
The only way to fix runout is fireforming/refireforming. A die cannot do it.
The primary cause of runout is thickness variance of a case.
The initiator of runout is sizing, and misaligned sizing can also directly cause runout of course.
A minor contributor is misaligned seating.
To make straight ammo you need to address the actual source/cause of loaded runout.
Culling cases by thickness variance, neck turning, minimal sizing and seating with inline dies, etc.
Once you've made crooked ammo, you can adjust only eccentricity of it, possibly with a cost of increasing runout further(neck bending). But concentric ammo that is crooked won't chamber and fire the same as straight ammo. It's not the same thing.
You can make it straighter by firing it in your chamber, and then try again to size & load it straight as measured on a runout gage.
Work out the bugs a couple times & you'll get real good at it across the board.
The NECO is an excellent gage if you're set on it. I just prefer Sinclair, and I also prefer their neck turning system, and neck thickness gages, yadda, yadda. I spend a bunch there I guess...