Expander mandrel sets

I am looking to up my game in the area of neck tension. I currently have a single expender mandrel for 6mm that I was using for 243, then for 6Dasher, and now, maybe for 6GT. I intend to tune my next round of loads using neck tension as the variable. Does anyone know of anyone who has decent sets of expender mandrels that don't break the bank, and are available in various calibers? I am not interested in $200+ per cartridge.
21st century
 
Measuring the run out of your seated rounds after using a bushing sizer can leade you to bang your head on the wall in frustration!

I have got my very best run out with Forster std dies, with the neck honed out at Forster($12 when you purchase the die from them), then use a mandrel. I did not come up with this method, I coped with a guy that tests bullets for Berger at 1000 yards.

Collet dies with various sizes of mandrels can also produce very, very concentric seated bullets, but this is NOT popular because it is different. Lee sells several sizes up and down from caliber in .001 increments. You can put the mandrel in a 1/4" drill and take the mandrel down to size with emory cloth and oil...slow and easy, slow and easy.
As Inspector Clouseaux (butchered spelling) said "very interesting ". For those of us who are old enough to remember him. Interesting process. Makes sense.
 
A mandrel can be used as a final NSing action. This pushes thickness variance outward, away from seating bearing, to allow low loaded runout.
The expansion also biases spring back continuance to an inward direction, so that tension does not relieve/reduce over time.
But tension itself, while sizing is shorter than seated bearing, is adjusted by sizing length.

There are three camps here where approaching bullet grip is completely different.
- FL sizing of necks
- Partial length sizing of necks
- Crimping

All three work provided a load is developed with it. If you want to include neck tension adjustments in development, then I suggest this as a last process. A final tweaking of load. Sometimes it makes logical sense to do it, sometimes it doesn't.

FL neck sizing brings interference as sized into tension, where beyond seated bullet bearing depth. This definitely causes the highest neck tension, but at a cost of highest tension variances. You bring donut area and shoulder angle influence, and binding at the bullet's base-bearing junction. It's not something I would ever do. If you suspect, through testing, that FL NSing will help, then you're using the wrong powder (too slow).

Partial neck sizing typically allows both interference and length of sizing adjustment (if bushing sizing). This offers high potentials with tension adjustment. You can reasonably downsize, and mandrel expand a reasonable amount.
Reasonable = less variance.
So you can start with sizing 1/3 neck length, and later try 1/4, or 1/2, or 3/4.

True crimping (mouth swaged into a bullet groove) is so dominant to bullet release that interference fitting with the rest of the neck matters less. While crimping is bullet grip, it is not tension. That can be a great advantage when you find a load that likes it, powder tune-wise.
A mandrel could be used with crimping done as a specific operation after mandrel use. Critical to crimp release would be neck hardness.
 
McMaster Carr has mandrels graduated in .0001 increments, you can really get down to the nitty gritty on the internal dimension of your sized neck which relates to bullet grip.

Lube in the neck introduces a new can of worms regarding bullet release. Lube in the neck may mitigate minor differences on bullet grip. Forster makes a simple and inexpensive set of brushes in a tray where you can lube with powdered graphite.

Varying amounts of carbon in the necks from previous firings skews the SD and Extreme Spreads, you can take that to the bank.
 
McMaster Carr has mandrels graduated in .0001 increments, you can really get down to the nitty gritty on the internal dimension of your sized neck which relates to bullet grip.

Lube in the neck introduces a new can of worms regarding bullet release. Lube in the neck may mitigate minor differences on bullet grip. Forster makes a simple and inexpensive set of brushes in a tray where you can lube with powdered graphite.

Varying amounts of carbon in the necks from previous firings skews the SD and Extreme Spreads, you can take that to the bank.
So to stop even small amounts of carbon in necks before bullet seating,a better cleaning protocol is necessary?
I think I need to make adjustments!
 
Thanks.I have the problem of hurry up and get it done syndrome.I can clearly see the case is not clean but I want to hurry and get it done!
I need to slow down!
A friendly reminder
I don't get them clean with the brush just one stroke.
Here was the results of my testing on neck "treatment" these were 10 shot groups

1) Nothing -Avg 2820 fps -ES 20, SD 7

2) Brush only -Avg 2813 fps -ES 13, SD 4

3) Brush with graphite -Avg 2813 fps -ES 6, SD 2

I'm planning on brushing all necks from now on and I will only add the Graphite to my ELR ammo.
 
Alternate neck lube making a difference is not a good sign. It means you're pushing the bullet a bit with release, which implies excessive tension. Ideally bullets would release cleanly without munging up optimum CBTO as set.
So, you could & should get similar result by simply lowering neck tension, and a quick brush through of necks is always a good idea.
But a light carbon layer IS the perfect lube.

Aside from logic, my basis is coating of bullets with WS2, the slipperiest of dry lubes.
I leave a single brush of carbon layer in necks.
My interference is purely within spring back range for ~1/2 neck length.
With this, I can switch from lubed or bare bullets with zero affect to MVs.
That's a good place to be for load development.
 
Alternate neck lube making a difference is not a good sign. It means you're pushing the bullet a bit with release, which implies excessive tension. Ideally bullets would release cleanly without munging up optimum CBTO as set.
So, you could & should get similar result by simply lowering neck tension, and a quick brush through of necks is always a good idea.
But a light carbon layer IS the perfect lube.

Aside from logic, my basis is coating of bullets with WS2, the slipperiest of dry lubes.
I leave a single brush of carbon layer in necks.
My interference is purely within spring back range for ~1/2 neck length.
With this, I can switch from lubed or bare bullets with zero affect to MVs.
That's a good place to be for load development.
The load I tested that on was sized with a mandrel .001" under bullet diameter. I will admit that the powder charge was not tuned at all it was just an arbitrary load I picked.
 
McMaster Carr sells mandrels that can be used in the Lee collet sizer. Some of the mandrels have to have an O ring on them to hold them in place, and infinite sizes are available. You can double-check the Inside dia of the neck with various sizes of mandrels ensuring that you have a consistent neck grip.
I use the Lee collet die alot. Any chance you could provide a link to the ones used in the LCD. TKS
 

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