Neck tension.

tinymike66

tinymike66

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So from research I gather my neck should measure approx 2 thou less than when seated with a projectile.
After FL sizing I seem to be getting only a 1 thou difference.
Can I neck size in addition to the FL sizing?

Also I have yet needed to trim my brass.
Brass has been consistently below min requirement and some up to 8 thou shorter.
Is this normal?

I'm using 6.5-284 lapua sizing up to 7mm.
Shooting a straight 284 win

Thanks
 
Do you use a bushing die?
My redding Fl die have different bushing you can buy to change neck tension
 
The brass is thinner at the neck as the diameter has been sized up by 0.5mm. Since it is Lapua and if it hasn't been neck turned, it is probably running around 0.010" to 0.011" thickness now. The full length die is likely made for brass which is nearer 0.013" wall thickness. The current thinner neck doesn't get sized down properly to provide the 0.002" tension for that brass. If you are using a bolt gun and you are getting sufficient tension that you cannot easily, by hand, push in the bullet then it should be ok if treated with care. It would still be best to neck size to a thou or so smaller than the current die is sizing to. If Lee makes a neck collet sizing die, and they probably do but I didn't look, it could be your least expensive option. Full length size like you do now and then run it through the Lee die before priming, etc.
 
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Two thousands is a nice number to aim for...but...if you are not having any problems, I wouldn't worry about it. Problems like the bullet moving in the case because of recoil.
 
Bullet doesn't move easily and I just seem to find a load and seating depth that gives me consistent accuracy, speed and one digit standard deviation......
But I don't mind investing in that Lee collet die if it will help out that much more.
 
If there is nothing broke, don't fix it.

1-2 thou interference is what I accept, I aim for 1.5 to 2 , of course that is not for hunting rifles.

If this is a single shot target rifle and it is shooting well I would leave well enough alone.
 
What is the diameter of your expander, you can polish the expander and reduce its diameter to increase neck tension.

Example at the Whidden custom die website they sell expander kits with five expanders. The kit has expanders from bullet diameter to .004 under bullet diameter.

With my Forster dies I can order the expander balls and polish them to the desired diameter.

At the Redding website with their bushing dies they tell you if you do not neck turn to use the expander and size the neck .002 smaller than the expander. And this pushes the neck irregularities to the outside of the neck.

Look at the link below and the charts showing how much the neck is reduced in diameter and how much the neck is then expanded.

Are Your Sizing Dies Overworking Your Rifle Brass?
http://www.massreloading.com/dies_overworking_brass.html

Bottom line even with a standard full length die and using different diameter expanders you have control of your neck diameter.

And with Forster dies they will hone the dies neck to your desired diameter.

FL Bushing Dies vs. Honed FL Dies
http://www.accurateshooter.com/technical-articles/reloading/fl-bushing-dies-vs-honed-fl-dies/

NOTE, at the Whidden custom die website they tell you they get the most concentric cases with non-bushing full length dies. Bushing dies work best with neck turned brass and tight neck chambers and reducing the neck diameter less than .004.
 
bigedp51 said:
What is the diameter of your expander, you can polish the expander and reduce its diameter to increase neck tension.

Example at the Whidden custom die website they sell expander kits with five expanders. The kit has expanders from bullet diameter to .004 under bullet diameter.

With my Forster dies I can order the expander balls and polish them to the desired diameter.

At the Redding website with their bushing dies they tell you if you do not neck turn to use the expander and size the neck .002 smaller than the expander. And this pushes the neck irregularities to the outside of the neck.

Look at the link below and the charts showing how much the neck is reduced in diameter and how much the neck is then expanded.

Are Your Sizing Dies Overworking Your Rifle Brass?
http://www.massreloading.com/dies_overworking_brass.html

Bottom line even with a standard full length die and using different diameter expanders you have control of your neck diameter.

And with Forster dies they will hone the dies neck to your desired diameter.

FL Bushing Dies vs. Honed FL Dies
http://www.accurateshooter.com/technical-articles/reloading/fl-bushing-dies-vs-honed-fl-dies/

NOTE, at the Whidden custom die website they tell you they get the most concentric cases with non-bushing full length dies. Bushing dies work best with neck turned brass and tight neck chambers and reducing the neck diameter less than .004.
Click to expand...

I use a Lee recapping die with a tapered 7mm expander rod.
My FL die is forster I took the expanger/decapping die out since I size up with the Lee.
I'll measure the expanders and see where they're at
 
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