In post 11, I wondered to myself if I used that Lee die and I shot a 5 round group from a cold clean barrel, would it group into one big hole. I did load em up, and in post 15 I said that 5 rounds from the Lee Collet Die did in fact shoot into one enlarged hole. I can't be sure of all the why's and wherefore's of them going into one hole, but it may have been due to Unclenick's mention (and I can't remember the exact words) that with use of the Lee die you could accidentally vary neck tension if you didn't resize them all the same way. In fact, I hadn't consistently resized all of the cases of the 15 shot group where 9 went into one hole, and I remembered that. So for the 5 shot group, I was particularly careful to resize the neck of each case with 3 strokes of the ram handle and the case turned about 1/3 of the way round for each stroke. And...5 in one ragged hole. I also loaded up 5 rounds with the FL die and the Bushing die (both with less shoulder setback), and the group from the bushing die was, as seen in the larger test, in last place.
I'm gettin way more consistency from that Lee die, and all I can assume right now is that it's due to concentricity. I can't measure that yet, since Sinclair hasn't sent me my measurement tool.
This has been a lot of work just to find out what die to use for ammo to plink crows in the front pasture, but it has been very interesting. I'm just a retired engineer with time on his hands that wants to know what ammo components and prep result in the most accurate ammo. Might as well. I shoot a lot, and what's the point of shooting inaccurate ammo. And I like impressing friends and neighbors. I tell em "here, shoot this one", and they get tiny groups and are amazed. I just smile. So when you and Unclenick (and FGuffey) are talking, I'm listening.