Note that with standard sizing dies size the outside of the neck enough so the thinnest spec brass will still be squeezed down enough. If your brass is not dead minimum thickness, it is over-resized in the standard die and the expander then resizes it back out again. That has the double drawback of working the brass more than necessary and the expander tending to pull the neck off-axis as the video showed. If you want to maximize case life you want to avoid the over-resizing and expanding. The two ways around that are the Lee Collet Die in the video, and the various bushing type dies, which allow you to pick a neck bushing that's the right size for your neck thickness so no expander is needed.
I have recently been sizing critical rounds in two steps. One step is the Lee Collet Die for the neck. The second is a Redding body die for narrowing and slight shoulder setback as needed.
Advantages the Lee die design has are: Because its mandrel sizes the inside of the neck it doesn't matter what the neck wall thickness is so there's no bushing to buy and select for the brass lot. Having no expander means you don't need to remove the decapper or put on an undersize expander to avoid pulling necks off axis when you use it. The mandrel prevents formation of an internal donut at the junction of the neck and shoulder. It costs a lot less.
The drawbacks to the Lee design are that there's a small learning curve in using it and getting the feel of it. Lee is not big on fine finish, so I usually end up taking the time to lap my collet dies for smoother operation and better feel.
The bushing die advantage is you can get a bushing type full-length sizing die so you can correctly size the neck and set the shoulder back in one step. If you also want to decap at the same time, though, you do need an undersized expander nut for the decapping pin chuck. You can lap down the one that comes with it by a thousandth by spinning it in a drill with some 600 grit wet/dry looped over it. That way it doesn't drag on the neck when the bushing is correctly sized and you still have something to take dents out of necks.
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