21st century
Expander mandrel sets
- Thread starter Bang4theBuck
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john k
Well-Known Member
As Inspector Clouseaux (butchered spelling) said "very interesting ". For those of us who are old enough to remember him. Interesting process. Makes sense.
Mikecr
Well-Known Member
Eccentricity and tension are different animals
Mike, conquer both animals at the same time. Some loads may like more/less tension as you well know.
Mikecr
Well-Known Member
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.
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.
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!
I've found brushing the necks will lower SD, adding graphite powder to the necks brought them down even farther.
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 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.
Yep I going to make some changes!I'm impressed.Big difference
Mikecr
Well-Known Member
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.
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.
I use the Lee collet die alot. Any chance you could provide a link to the ones used in the LCD. TKS
