Using a mandrel to size necks

[Monterey21]

Yeh its probably an annealing issue to at times.

That's interesting from Redding, never heard or read that before!
Would that be to probably more pressure needed to seat & not good for the stem?

That's exactly what the issue is. In the instructions they warn against using the competition seating die with Compressed loads. Redding should put this in the product description up front. I have competition sets for 28 nosler and use Forester Competition dies for seating. I expand with the 21st Century tools. But the hardness is the biggest variable. Spring back varies from the hardness. For best results turn in the beginning, then anneal, clean, resize, expand, and seat. the last thing I do to fine tune the accuracy is sorting the cases. That is a can or worms in itself. My goal is sub.500" MOA.
these steps are MY evolution.
for what it's worth.

 

[clownbuster]

Ok guys got a questions for the experts. Looking to make my loads as consistent as possible . What is your thoughts on sizing without an expander ball and then running a mandrel in the neck to set your neck tension. Can you even buy mandrels of different sizes and if so where. Or is it better to just size with a bushing die without an expander ball. Any input is appreciated. Thanks In advance great info on this site

Great question Dirtdevil. Correct, ditch the expander ball. My typical setup for controlling my TIR (Total Indicated Runout):
-Anneal
-A Forster FL sizing die honed to size neck .004" under final sized neck diameter with the expander ball removed.
-Set neck tension running cases thru a TiN Turning Mandrel (21st Century) for a final neck diameter of .002" neck tension. Runout hangs in the 0.0005"-0.0015" TIR range, which means actual runout is half that.

 

[James Darnell]

NOE (Night Owl Enterprise) makes 2 step M-die style expanders that fit the Lee Universal expander die. They are available in a large variety of diameters and are only about $6 each.

 

[Jeffrey Van Zandt]

Ok guys got a questions for the experts. Looking to make my loads as consistent as possible . What is your thoughts on sizing without an expander ball and then running a mandrel in the neck to set your neck tension. Can you even buy mandrels of different sizes and if so where. Or is it better to just size with a bushing die without an expander ball. Any input is appreciated. Thanks In advance great info on this site

https://www.accurateshooter.com/technical-articles/neck-turning-basics/

 

[ar10ar15man]

they are talking about sizing down with a std die..that way under sizes the neck way too small...not bushing size to a desired dia.

Yeh its probably an annealing issue to at times.

That's interesting from Redding, never heard or read that before!
Would that be to probably more pressure needed to seat & not good for the stem?

 

[65WSM]

I use the K&M expanders often to get the neck tension I desire. If I have turned the necks on the cases, I often get more consistant neck tension, measured with the K&M dial indicator on their arbor press, with expanders than I do with outside neck bushings. Full length size dies usually produce 4 thousandths under bullet diameter. I like to have 1.5 to 2 thousandths and the K&M expanders will deliver that. I use the Sinclair die and expanders too, on occasion, to get similar neck tension.

The Wilson bushings are another tool that deserves mention. The bushings are tapered inside half a thousanth. If you turn them around, then you can get a half of a thousandth of neck tension.

Consistant neck tension is second only to consistant seating depth in long range accuracy.

 

[COBrad]

That was a good article on neck turning. I turn all my necks to the same thickness, calculated after measuring 10% of the cases. I take just enough to make them consistent. Any with over .003 variation are culled and used to set up tools. I start with good cases like Norma, Lapua, and RWS. I then use a bushing die for neck sizing and usually size 80% of the neck leaving that last little bit to align the neck precisely in the chamber.
Or if it's a rifle I don't expect or need sub- moa accuracy I sort by neck thickness and cull any that fall outside a +or- .001 variance.

 

[aushunter1]

they are talking about sizing down with a std die..that way under sizes the neck way too small...not bushing size to a desired dia.

Ah, no Im using a bushing NK die so would be way less sizing @ 20 thou neck tension.

Yeh I never felt to much resistance in my comp seater without using a button

 

[snowypeakoutdoors]

Redding body die and Lee Collet or Redding Bushing dies with correct bushings.

 

[MagnumManiac]

Well I went the opposite way.
Was sick of donuts, ditched the bushing dies and started using Forster FL Benchrest dies with honed necks, sanded and polished expanders that float.
My concenticity dropped to barely readable on a .0001" accurate depth micrometer. A few tenths is the maximum run out I get now on my comp stuff.
I have also honed several RCBS & Redding dies now with very similar results. Run out is barely .001-.0015" even on hunting rounds, which are precision handloaded just like my comp stuff, only the run out is a little more. I still use mandrel when setting up comp brass for turning and stubborn cases that springvack too far.

Cheers.