Bought a Lee Collet neck sizer in 30-06. I was very disappointed at first; it wouldn’t size the neck down enough to securely hold the bullets. Rather than toss it, I did a few things that really made a difference, and now am very happy with it. This is the procedure that helped me:
1) Chuck the mandrel in an electric drill, and using fine sandpaper, then finer yet, polish the mandrel down a bit, around .001”. By using a wider piece of paper around the mandrel, and by holding even tension along its length and running it up and down as the drill is spinning, a uniform diameter can be maintained. Recognize and bear in mind the portion of the mandrel that the case neck is actually sized on.
2) Polish out any gouges or galling that you may have caused on the “fingers” through excessive pressure, which if you are camming your press over you will almost certainly have done. Clean them and the collet well, then coat contact surfaces of both with good quality EP (extreme pressure) grease. Keep them lubed.
3) Turn the aluminum cap into the die, tightly compressing the o-ring; engage all of the threads possible.
4) Read and follow the instructions, set the die so that you cannot cam the press over.
5) Following advice given on this forum, I now stand relaxed beside the press to do the sizing; I find I can easily apply more consistent pressure in this position by leaning on the handle rather than working it while seated. Much less tiring as well. For me.
With everything polished up and lubed well, I can feel the neck being squeezed down, and can also feel when it has gone far enough and is done.
