Neck down brass shoulders still crumpled after firing

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Neck down brass shoulders still crumpled after firing

Post by upup » 18 Feb 2014, 10:15 am

Hi guys.

New reloader here needing some help.

I've recently had a go at necking down .308 brass to .284.

In the initial resize a few cases had slightly crumpled shoulders. Only light though so no worries there, it's gunna happen on a few on that initial step down...

So I resized them, loaded them, fired them all no problems. The hand loads shot well and the brass fireformed back to its proper shape.

The problem... I neck sized all the now fired brass, but a few of the shoulders have crumpled slightly again.

I would have thought after a firing that everything would settle in?

Have I gone wrong somewhere?
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Re: Neck down brass shoulders still crumpled after firing

Post by Apollo » 18 Feb 2014, 10:27 am

First thoughts are that you have set the Neck Sizing Die too low and it's pushing on the shoulder. It should not even touch the shoulder.

Soot a case with a match, candle, lighter or whatever and put it in the die and see how far the soot is removed or marked.

Wipe out you die afterwards to remove any remaining soot.
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Re: Neck down brass shoulders still crumpled after firing

Post by AlanK » 18 Feb 2014, 2:41 pm

If not the sizing die being too low like Apollo said, it could just be a matter of firing it once more before things 'settle in' as you say.

Like you've touched on, when you size the neck down there is quite a bit of pressure going down on the neck for the initial resize. The neck wall will increase in thickness too.

A single firing might not necessarily enough to stretch the neck enough to thin it out to standard thickness. It could still be a little thick and that little extra pressure is forcing a shoulders to crumple still.

If it's not the die being too low, I suspect the problem will resolve itself in the next firing or two as the neck continues to stretch and thin.
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Re: Neck down brass shoulders still crumpled after firing

Post by Ken » 18 Feb 2014, 6:38 pm

Something as simple as just not enough lube in/on the neck could be contributing too.
Whatever you do, don't look at the mayonnaise...
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Re: Neck down brass shoulders still crumpled after firing

Post by Antie » 19 Feb 2014, 3:14 pm

Reminds me of the movie Evolution.

There's always time for lubricant!!!

:lol:
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Re: Neck down brass shoulders still crumpled after firing

Post by upup » 12 Mar 2014, 9:22 am

Thanks for the replies guys.

I've had another day out with the brass since last comments.

Did a careful walk through through of the sizing process and everything and am confident I had it right the first time.

This time around I only had a single case shoulder crumple so this are getting better.

I think I can maybe chalk this up to neck thickness issues from sizing down.

I'll continue to monitor but it seems the problem is resolving itself :)

Thanks again.
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