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Call for Help

18 Mar 2017
@ 05:20 pm (GMT)

Paul Leverman

I need help figuring this one out, so I am calling on you to voice your opinions or experiences. None will be discounted, as I have totally run out of ideas or solutions.

I bought the NoslerCustom brass. Reformed it from Winchester to Norma. All it took was to run it into a F/L 308 Norma Mag die, then trim to length. Simple, effective.

Made a mandril to fit the sized neck (-0.0005") and checked neck wall thickness. All were within half to three-quarter thou of each other.

Run-out on the necks were anywhere from zero (not quite, the needle moved, but just) to two and one half thou. Unfired.

Loaded up a bunch with whatever recipe I was testing. When I checked them after fireforming, none had stretched much, none had more than a thou of run-out. This tells me the chamber is good doesn't it?

When I went to re-size them, I used a Redding bushing style neck sizing die. Set up the die as usual (as per the instructions, plus I trued the decapping rod and expander as per the Hornady method.) The first three cases were fine. The next three had over five thou run-out. My first thought was the brass had an anomaly in the necks, so I carried on. The seventh had about four thou run-out, then two came out perfect.

I separated good from bad and marked high spots, and ran them through the die again, rotating them by one-quarter turns to see if it made any difference. On two cases, it reduced the run-out. It cured one case to perfect. The rest remained as they were.

I disassembled the die and cleaned it, just in case. Ran the bad ones through again, no change.

I removed the decapping pin, thinking that it may distorting the necks on withdrawal, but no, that made no difference. On a whim, I took a fired case that hadn't been sized yet, cleaned it, lubed it and ran up into the die. It came out with four and a half thou run-out (from zero).

I found it hard to believe that a die that had performed flawlessly previous to the Norma had all of a sudden developed a fatal flaw, so I started looking hard at the press.

I removed the shell holder, replaced it with another brand (same size) and tried more brass. Same results.

Took the shell holder out, cleaned the ram where it clips in, tried it again, same results.

Took the press apart and measured the bore that the ram works in. It was out of round by less than half of a thou. Measured the ram. I guess after twenty some odd years, something has to wear. At the top end of the stroke (bottom of the ram) it had worn one and a half thou. Enough to give it three thou of lateral movement at the shellholder end at the top of the stroke. Well, that was a cause for celebration. I had found my problem, or so it had seemed. Unfortunately, I had not.

I was just going to make another ram, but then thinking about the problems I already have, if I made a one thou mistake in machining, what would that translate to? So, time for a new press.

Installed a Rockchucker Supreme on the bench. Started over again with the brass and damned if I still didn't have the same results.

The next step (grasping at straws now) was to buy a new Redding neck sizing die in Norma mag. Nothing fancy, no bushings, just a die. Well, that didn't work. Even with removing the decapping rod, I still got the run-out.

So, basically I gave up.

The next morning, I sat there and stared at the whole mess trying to see if there was any combination I may have missed. Two different presses, two different dies, same brass, same results.

Out of pure frustration that I had quite possibly just ruined my new brass, I put the F/L Norma die in the new press. I knew I could get new brass almost perfect with it, so what the hell, try it. And it worked. If the brass didn't return to like new the first time, a second time through and it was just as good as when I started.

So this told me that it was not the brass, not the press, not the technique.

I re-installed the Redding neck die (non-bushing) and ran one into it. It came out perfect. So did the second one. But not the third or the fourth or the fifth. Back to the same old run-out problem.

So that's it. What did I miss? What is wrong with my technique that would cause an intermittent problem like this? I really don't want to F/L size my brass every time I load it. Any ideas to try to fix this would be greatly appreciated.

I know the solution is staring me in the face, but quite possibly I have worked myself into an irreversible state of frustration that has locked out my cognitive thinking.

Replies

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31 Dec 2019
@ 01:59 am (GMT)

Paul Leverman

Re: Call for Help
You may want to make your inside chamfer a little deeper, but not to the point of sharpening your case mouth. Boattail bullets also help in conjunction with the chamfer.
02 Jan 2020
@ 12:05 pm (GMT)

Francis Saunders

Re: Call for Help
Ok thanks Paul makes sense, I’ll try that.
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