Resizing with full length or neck sizing die?

[flashhole]

Does this relate to the fact the K&M neck turning tool requires the use of the K&M expandiron to attain the proper neck ID so their mandrel can be inserted into the case neck to facilitate turning?

 

[woods]

I'm sure Mike will be along directly and give us his answer, but IMO it would be a good idea to make the ID of the neck consistant. If you have variances in neck thickness then the ID of the neck would reflect those inconsistancies.

I did a test sizing with 3 methods: Lee Collet, FL die with expander and Redding bushing die. The necks on the cases sized with the bushing die were outside neck turned, a complete turn, not a skim. Then I gauged each set of 5 cases with pin gauges to .001". The pin gauges also give a little further information in that you can estimate ID smaller than .001" by how tight or loose the pin gauges go in. The Lee Collet had no variation, the expander ball cases varied but very very little (maybe .0005" or so) but the bushing die case (sans expander) varied by as much as a little more than .001".

So IMO it is difficult to get a 100% consistancy from an outside neck turn and that is reflected in the variance on the neck ID when sizing the OD to a set dimension with a bushing.

 

[flashhole]

Using the collet die I wouldn't expect to see any ID variation even if the necks had not been turned to a consistent thickness. Interesting comment about the bushing die. I don't use one but have been wondering if I am missing out on something.

 

[Mikecr]

Does this relate to the fact the K&M neck turning tool requires the use of the K&M expandiron to attain the proper neck ID so their mandrel can be inserted into the case neck to facilitate turning?

Yes
For turning, expansion needs to result in a close match to the turning mandrel.
I ditched K&M turning because this operation left me with necks that had to be sized down afterward for loading(their mandrel diameter is too large). It's not a big deal in itself, but then their 'expandiron' wouldn't be right for me either(expand too much).

I've yet to run into any surprises with turning. Measured brass thickness, thickness variance, bullet diameters, turning amount, & loaded neck diameters.. All work out as mathmatical.
The variance Woods sees with IDs of bushing sized necks isn't surprising as the final operation of neck sizing is not yet completed(EXPANSION).

For those interested in JLC dies, here's a brochure: http://www.6mmbr.com/CarstensenJLC01.html
There was a brief discussion about bolt click that Boyd summed up nicely here: http://benchrest.com/showthread.php?71627-quot-Bolt-Click-quot&p=597321#post597321
Bolt click(popping extraction) is a problem competitors run into that is a top irritant because it mangles their runs. They're combating this specific problem(which they are directly causing) with misplaced notions that are long extinct..
Their problem AND solution is excess pressure. I say it's both, because they currently need high pressures to be competitve(in 6PPC), and of course there is a price for it. Neither greater sizing nor greater clearances will escape the results of this root cause.
But this is their bubble. Their tiny little world. We don't have to run extreme pressures. We have our pick of cartridge cases and powders to get the job done within rational.
WE ARE NOT THEM