Body die and Lee Collet vs FL sizing?

[Dos XX]

Why not a full length sizing die with neck bushing of the correct size, no expanding mandrel?

 

[Wrench]

The beauty of the collet is if brass is thicker in an area it still sizes to the middle. The bushing will push the fat side tighter and the ball then works it back.....hopefully centered.

 

[wapitibob]

Why not a full length sizing die with neck bushing of the correct size, no expanding mandrel?

That's essentially what I did with stw brass but used a neck bushing die and a body die for the shoulder. It worked because the Nosler bras had .0005 wall thickness variation. My PRC ADG brass varies neck wall thickness by almost .002 so I need to use a mandrel to get consistent neck tension.