6.5 cm lapua brass- ever seen this?

nmbarta

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billings mt
My last two sets of Forster dies have narrowed the case at the shoulder quite a bit, from fired dimensions, .005”. This is significantly more than my Redding body dies do. I’m wondering if that might have the same effect as pushing the shoulder back too much.

John
Brass will only tolerate so much movement, it doesn't matter which direction. Brass work hardens with every shot/sizing cycle. Annealing can help with this, but many if not most who aneal aren't doing themselves much good.
In my experience, an average case will tolerate about .020 of movement. Meaning that if you move the shoulder .002 you will see a failure in the body of the case somewhere around the 10th firing if your primer pockets hold up that long.
If you move the shoulder .050 you'll likely see a failure around the 4th firing.
Some people who Neck size, and only FL size every 3rd or 4th with medium loads are getting upwards of 20 shots, I've never seen anything close to that.
In most cases (pun intended) I'm happy with 8 firings.
 

Gord0

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You bumped the shoulder back .003-.004" after the first firing. Your first firing more than likely never fully formed the brass to your chamber. I would guess you have been excessively sizing it.
 

bigedp51

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Schnyd112
You are bumping the shoulder back as much as someone with a M14/M1A semi-auto rifle. With a bolt action normally .001 to .002 shoulder bump is all that is needed.

Below FYI
The .308 Winchester cases below were fired in a brand new Savage rifle. The dies were adjusted per the instructions with the die making hard contact with the shell holder. No information was given about the amount of shoulder bump. Meaning this is "ball park" information and not written in stone.

TDwPD1Q.jpg


XEuny9C.jpg


Suggestion, buy some Redding competition shell holders, these shell holders will "NOT" push the case as far into the die as a standard shell holder. There are five shell holders in .002 increments from .002 to .010 less shoulder bump. You start with the +.010 shell holder and work down until the bolt will close with the proper amount of shoulder bump.

Below with the proper amount of shoulder bump you will be .001 to .002 below the red dotted line. And this is well within the brass elastic limits and prevents case stretching and thinning.


wm05ArY.gif
 

Schnyd112

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Northern Nevada
So I am sending my die in to get honed out to .289 in the neck but I can’t do it until the end of November. Right now I am seeing .284-.285 necks right now when I size brass without the expander. I also want to try and size without the expander and just use a mandrel if I need to expand the necks.

I want to full length size, especially if I am dealing with a sloppy chamber, because it is a competition rifle and I want to start from the same spot every time. I just haven’t seen the advantage to neck sizing and body sizing in different steps. No matter what, you eventually need to full length size and start over.

I don’t want to buy new dies because I am not super impressed with the creedmoor and my next barrel will be something else.

You bumped the shoulder back .003-.004" after the first firing. Your first firing more than likely never fully formed the brass to your chamber. I would guess you have been excessively sizing it.

If I were shooting something where I was changing the shoulder angle or moving it forward or changing caliber I would think the same thing. I would not think am failing to fully form the brass to the chamber as it already starts very close to final dimensions every way I can measure it.

I have 5 new pieces that I have expanded the necks on a mandrel and won’t full length size for a few firings, just to see. Neck tension is a little light but they will be single shot and are just an experiment.

Schnyd112
You are bumping the shoulder back as much as someone with a M14/M1A semi-auto rifle. With a bolt action normally .001 to .002 shoulder bump is all that is needed.

Below FYI
The .308 Winchester cases below were fired in a brand new Savage rifle. The dies were adjusted per the instructions with the die making hard contact with the shell holder. No information was given about the amount of shoulder bump. Meaning this is "ball park" information and not written in stone.

TDwPD1Q.jpg


XEuny9C.jpg


Suggestion, buy some Redding competition shell holders, these shell holders will "NOT" push the case as far into the die as a standard shell holder. There are five shell holders in .002 increments from .002 to .010 less shoulder bump. You start with the +.010 shell holder and work down until the bolt will close with the proper amount of shoulder bump.

Below with the proper amount of shoulder bump you will be .001 to .002 below the red dotted line. And this is well within the brass elastic limits and prevents case stretching and thinning.


wm05ArY.gif

I don’t have the Redding shell holders but I do have several that are about .004 apart. It’s not perfect, I can’t adjust and get a reading between 1.535” and 1.537” it is one or the other, but I am getting consistent measurements. I would like to try a different tool/comparator to measure the shoulder if anyone has a suggestion. I am not sure I fully trust the hornady tool, it seems too universal to give a consistent measurement to the thousandth.
 

Schnyd112

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504
Location
Northern Nevada
Is there a chance I am pushing the shoulders back when I seat bulllets and that is causing the headspace problem?

Kind of a wild *** guess, but like I said these dies have always seemed tight. The seater dented bullets really bad when I first got it. I have had to polish the stem a couple times because it expands and gets stuck inside the spring loaded part of the die.
 

MagnumManiac

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Feb 25, 2008
Messages
3,971
Pushing the shoulder back when seating bullets only really happens if the crimp ring is touching the cases mouth.
Seeing it’s a Forster die, you MAY have it adjusted incorrectly, but that’s doubtful.

I’ll give you an examle:
I have an RCBS FL 338WM set that sizes the neck .335” (ID) and the expander brings it up to .336” (ID). When sizing, the ‘feel’ is not there when the expander passes through the neck, this is how ALL of my dies are set up, all have honed necks and polished expanders.
This brass has never split or required trimming.

When I was using bushing dies, I had trouble with donuts, I moved away and started honing necks of dies, it works far better for me.

Cheers.
 

jsthntn247

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Jan 14, 2009
Messages
779
Next time you resize, check your case to chamber fit by removing the firing pin from the gun and chambering a piece of brass after you size it and the Hornady gauge says .000 movement then bump back to .001 then .002. Etc. With the firing pin removed you will be able to feel the case to chamber fit and when the handle drops and you can’t feel the case it’s sized enough. That might be at .000, then you wright that number down and that is your headspace for that chamber and your Hornady gauge.
 

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