lee collet dies/rcbs dies/foster bonanza dies/who's dies are best?

[Trickymissfit]

I think if one wants to just open up their full length sizind die's neck to a couple thousandths smaller than a loaded round's neck diameter, then turing the die in a lathe chuck is best. That'll keep the die's neck well centered on its body axis.

For making a "body" die, then drilling out the die's neck on a drill press would do just fine.

Regarding body dies, are they typically just going to size case body diameters down and not touch the shoulder at all? If so, what's wrong with just cutting off the die's top end at its shoulder?

That's pretty much what I always did, but still left a small amount of the neck inplace (opened up)
gary

 

[Bullet bumper]

Body dies still touch the shoulder because you need to bump the shoulder back now and then.
To make one out of a full length die you do cut some of the die off at the top but as Tricky says it is better to leave some of the neck area otherwise if you cut right down to the junction of the neck and shoulder a sharp flaky edge would result .
I would not make one that way.