7mm STW Dented cases & cracked above the belt?

Cinchy

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I shot a few rounds today & everything seemed ok, chambered easily , no hard bolt life or extraction? When I got back home I decided I would resize the shells so they would be ready to load as I shot the rest. First shell I tried to run thru the sizer the head came off inside the dang sizer? I started to inspect the fired cases & noticed some big dents right below the shoulder & almost all cases looked like the were cracked above the belt wit black soot showing? They are Hornady cases & I believe that was there 4 loading and I had annealed them before loading. Some of the shells look like they have a very faint crack & some have carbon showing in the cracks, I`m surprised they didn`t separate when ejecting from rifle. What in the world is going on & any suggestions on getting the stuck shell out of my resizer die. Should I just scrap all the remaining brass that has not been loaded, I was well below max on all of them that cracked.
 

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milo-2

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Try a tap to get the case out. Don't use one so big you scratch the die.
Classic casehead separation, yes, pitch all the brass. The dent up by the shoulders is from gas escaping from the cracks in the brass above the belt. Usually caused by overbumping the brass. But excessive case growth can occur easily with belted magnums.
Inspect your chamber, make sure gases didn't do any cutting of the chamber walls.
 

Cinchy

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milo-2 Thanks for your reply there was only 2 cases with bad dent, so Ill keep my fingers crossed on my chamber. I have a neck size die to get by till I can find a full length die if I can`t get stuck case out.
 

Hard rock

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milo-2 Thanks for your reply there was only 2 cases with bad dent, so Ill keep my fingers crossed on my chamber. I have a neck size die to get by till I can find a full length die if I can`t get stuck case out.
I would check headspace primers look backed out also case head separation is a definite sign of excessive headspace getting that stuck case out will be a lot harder without being able too use a stuck case remover being the case head is gone be careful until you verify the issue
 

Roninco

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By design belted magnums have excessive clearance between the case shoulder and chamber; especially in factory guns.
Belted magnum cases may take several firings to fully expand to chamber dimensions. If you bump the shoulder back after only one firing the case will continue to excessively grow and result in the case failure you are experiencing.
Neck size only until the fired case rechambers with resistance then full length resize to bump the shoulder a minimal amount.
Any cases reloaded in your current batch should be discarded. They have over stretched above the web and are likely to crack.
 

Cinchy

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I noticed in 1 of the pictures the primers look backed out to, but I believe its just a shadow ? All the primers feel flush when you run your thumb across them, maybe seated just a little below ?
 

MagnumManiac

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Case design and other BS is not the cause of ANY case head separation.
There’s only ONE cause and that is RELOADER INDUCED EXCESSIVE HEAD TO SHOULDER CLEARANCE.
I does not take several firings for a belted case to reach the shoulder, just as it does not with a rimless design.
If you are Fl sizing your STW brass, then you are moving the shoulder too much.
As noted, size only enough after the first sizing so there is a little resistance on closing the bolt.
Better still, buy a case head space comparator tool, this way you can keep track of how much bumping you are actually doing.

Cheers.
 

MagnumManiac

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I had enough trouble reloading belted magnums that I ended up buying one of the ULTRA Magnums--no belt..
If you push the shoulder back too much on that case…you will still get case head separations.
It is a common misconception that problems are caused by the belt, the belt does nothing after the first firing other than being there. It no longer controls headspace and should be ignored, but too many push their shoulders back too far and blame every problem on the belt.
I have NEVER had a case separation on a belted case, not once! The reason is because I understand how to size my brass so that the shoulder controls the headspace after the initial firing and, if you size so the case is tight from base to shoulder the first time, you encounter zero problem from then forward.
Anyway, that’s how it is.

Cheers.
 

MagnumManiac

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Same here but I purchased this a few years ago just in case ...

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I had a personal argument with Mr Willis about case head separation and case bulges when he first had his reasons and falsehoods promoting his die….I’ve never needed it or seen a bulge on a single belted magnum case. But I don’t run rifle chambers that don’t fully support the case head. I still have the case I sectioned that had been sized 10 times, no case bulge, no stretching at the web and the case would have seen another 10 loads if I hadn’t cut it lengthwise to illustrate that CORRECT SIZING will have no detrimental effects on a case, even a belted magnum.

Cheers.
 

FEENIX

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I had a personal argument with Mr Willis about case head separation and case bulges when he first had his reasons and falsehoods promoting his die….I’ve never needed it or seen a bulge on a single belted magnum case. But I don’t run rifle chambers that don’t fully support the case head. I still have the case I sectioned that had been sized 10 times, no case bulge, no stretching at the web and the case would have seen another 10 loads if I hadn’t cut it lengthwise to illustrate that CORRECT SIZING will have no detrimental effects on a case, even a belted magnum.

Cheers.
That's fine; I am a sucker when it comes to innovative minds, and "I" consider this well-engineered reloading tool as an innovative advantage when the need arises. No one person or company can satisfy everyone's needs or satisfaction.
 

xsn10s

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Mar 7, 2016
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Dented shoulders on the bigger 7mm cartridges could be a sign of a double pressure spike. I think it was with slower powder, sorry I cannot remember the details. I saw it once on the 7 RUM with certain powders. The thought at the time was the first pressure spike was enough to lodge the bullets into the lands but not seal the case in the chamber thus the dent on the shoulder. Then the second spike would generally be high.
 

jimbires

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clearfield county , Pa
from my experience Milo-2 nailed the problem . the cracks caused the dents .

when sizing new brass , I neck size only until the brass gets fully expanded . you will be able to tell when it's fully expanded , it gets tight to chamber . this will take 3 or 4 reloading cycles . when you get the brass fully expanded , NOW you can set up your die to bump the shoulder .002" . if your setting up the die on brass that is not fully expanded , you are over sizing .

edit to add ;

call the die maker , I'll bet they will remove the piece of brass from the die for you .
 
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