Case forming for accuracy

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  • Last Post 24 October 2018
38splpete posted this 23 October 2018

What about necking down 400 Whelen brass to obtain thick neck walls which could then be turned to a thickness that would be a tighter fit in 30-06 military chambers?  It would be expensive--the brass from Midway is over $2 ea--then a 35 Wheeler FL sizer would be needed as an intermediate sizing step, I'm guessing.  Maybe other sizing steps would be necessary--say 9.3 X 62, then 35 Whelen, 8mm-06 and finally 30-06.  A lot of work for little, or possibly no gain?  It's an idea I've had for some time--ever since I tried necking down some Win 35 Whelen cases to 30-06.  Didn't gain even a thousandth in neck wall thickness.  I think that the 35 Whelen brass was formed at the factory simply by expanding 30-06 brass.  I doubt that would be the case with the 400 Whelen brass--it ought to be pretty thick when sized down.  Anybody ever tried this?

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Brodie posted this 23 October 2018

Wouldn't it be a whole lot easier, and probably cheaper, to just take the rifle to a gunsmith, and have a couple of threads removed from the barrel and a minimum chamber cut into it?  I mean after you buy two or three dies (or possibly sets of), two dollar apiece brass.  And possibly loose several in the forming process all to little or no accuracy improvement.

B.E.Brickey

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RicinYakima posted this 23 October 2018

Oh grasshopper, I have tried that trick before. (Old Coot, if he is going to shoot CBS Military matches, that would be illegal and unsporting. Issue barrels and chambers only are allowed.) It will lead you to hair pulling and saying bad words. After years of chasing that rabbit, I found that only sizing 80% of the length of the neck allowed the case to center just as good as anything. I put an 0.080" feeler gauge on top of the shellholder and then set the sizing die. I don't wipe the lube off the case and it fireforms with no headspace and centered in the chamber. FWIW, Ric

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Ross Smith posted this 23 October 2018

If you must, go ahead. I have to make my brass for the 308x1.625 ardito. It is a short 308. However 308 brass doesn't make the best cases, 30-06 do, and I squeeze them down in one step. End up with a case that is short with a really long thick walled neck. The neck is trimmed to length and then either inside reamed or run a neck expander down and trim outside on a lathe. Lotta work.

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Ken Campbell Iowa posted this 23 October 2018

the thicker neck trick has been tried by the * no-expense-spared *  mj benchrest guys .... as of 2008 or so it hadn't improved groups.   there even have been some top shooters use looser neck chambers with no accuracy penalties .

apparently caster shooters aren't the only ones that don't have a whole lot of iron-clad rules for accuracy ...

miss _Precision Shooting_ ... always hoped the very next issue would reveal the final secret ...

ken

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RicinYakima posted this 23 October 2018

"miss _Precision Shooting_ ... always hoped the very next issue would reveal the final secret …"

Me too. They still owe me 2 years and 10 months of my last full paid subscription! Think they used my money to go to their favorite tavern and drink craft beer they were always talking about.

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38splpete posted this 23 October 2018

Ric, Ken, and others--thanks for the comments.  I guess that idea will be relegated to a wayy--back burner.

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shastaboat posted this 24 October 2018

Shooting cast lower pressure bottle neck case rounds may allow you to shoot a tight necked chamber but remember with high pressure jacketed rounds you need the neck expansion to control pressure.  Shoot high velocity rounds with little expansion in the neck will at minimum blow primers in those loads that may be completely safe in a larger necked chamber.

 

Because I said so!

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