Originally Posted By: Verminator2Cat, why don't you recommend the Type S bushing die? Does the body sleeve make a large difference or do you like to partially size the neck?
OK... here is what it is. And it makes no difference whether you are sizing the whole neck or part of the neck - it's all the same same.
I started using "S" bushing dies right from a looong time ago.
Now, use your mind and picture what I am talking about as I go.
When you have a case (like the 22-250), and you run it up into a neck size die (either a plain die, or a bushing "S" die)... the case has taper, so it goes in but does not touch ANYTHING... until the mouth hits either the base of the dies shoulder/neck junction, OR the entrance to the bushing - at this point, the case is still NOT touching anything.
So... you could actually cut away the whole body of the die, and just have the shoulder and neck part in the press, or JUST THE NECK PART... and the case would touch the same thing, just the neck or bushing - are you still with me?
OK... now, since the case does not touch anything and the neck gets sized without support or guidance, then if the neck is not uniform in thickness, or the anneal is not uniform, the thin (or softer) part of the neck will move more than the thick/hard side of the neck.
So, Voila - we just made run-out that was not there before we neck sized the case.
Now, I will be the first one to admit that none of this occurred to me for a long time - I was happy as a pig in poop, just sizing away with my "S" dies thinking that I had the best that there was. I got run-out, but thought that "some run-out" was inevitable.
I had seen the "Comp bushing Neck Sizers" in the catalogue, but I thought they were the same as a bushing "S" die but with a micrometer, and who needs a micrometer to set the sizing depth of a neck - not moi!
Then I bought a 6mmBR benchrest rifle, and the only dies I could find in stock was a complete Comp set. So I bit the bullet and bought it. Later, when I checked my cases for run out, I was getting 1/2 a thou (0.0005"), which is unheard of... and not a few cases, but all of them.
So I gave it some thought and here is why it is so freakin' good.
In the "S" die, nothing supports or aligns the neck, even at the end of the stroke. You could actually put the bushing up there without a die, and it would work the same.
In the comp bushing neck die, the shoulder is a male cone, and the floating sleeve is a female cone - the case goes up into the sleeve and the shoulder and neck are FORCED into alignment with the axis of the die, BEFORE the bushing even touches the case.
Once the case is in there, with spring pressure forcing it in tight, no side force can move the case out of alignment because of the "Cone in cone" arrangement.
So, in effect, the case is locked in the sleeve, concentric with the axis, and the bushing is "lowered" down down onto the neck, which cannot move off the axis, no matter what.
So, now I only get Comp Busing Neck Sizers for high accuracy rifles if they are available.. if not, I get the bushing "S" dies.
Make sense???
