Author Topic: Best ‘hold down’ die for swaging and priming  (Read 183 times)

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Offline Clint007

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Best ‘hold down’ die for swaging and priming
« on: September 12, 2019, 12:52:23 AM »
I now have a Mark 7 Evolution. I have several more stations than with the 1050.

I’m loading 9mm.  I have a dedicated expansion/bell station between priming and powder drop. The swaging occurs prior to priming. A hold-down die is suggested at swage. I used a Dillon .32 cal back-up rod/expander from a 1050. I figured this would not touch the case wall.  It contacts the inside base of the case, holding it down during swaging.  But I just noticed something. It would appear that it’s flattening down a little metal lip around the flash hole?  Is this brass lip a product of the primer detonation?  The result varies case-to-case. I’m sure such a variation in flash hole will affect propagation of the the primer detonation and powder ignition process in an erratic way. Here are links to 2 cases, each before and after swaging.

I will change to using a Dillon resizing die with the depriming rod removed as my swage station back up rod....unless you Jedi Masters have other suggestions?   I think I should have a similar back up die at priming, also....to stabilize the case...

https://www.dropbox.com/s/t4frs67kjbo26yu/IMG_9976.JPG?dl=0

https://www.dropbox.com/s/tsyyt6fr3dkh7cs/IMG_9977.JPG?dl=0

https://www.dropbox.com/s/5wg04onfd1j02e2/IMG_9978.JPG?dl=0

https://www.dropbox.com/s/dxzchi4fnkejhtn/IMG_9979.JPG?dl=0

C
Huh?

Offline painter

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Re: Best ‘hold down’ die for swaging and priming
« Reply #1 on: September 12, 2019, 06:28:50 AM »
The metal you're seeing is the burr left when the flash hole is drilled. Precision rifle guys deburr their flash holes to assure consistent ignition. They make tools for the job, but most are all hand operated.

At the volume you're shooting you would be an old man with arthritis by the time you got all your cases done.
« Last Edit: September 12, 2019, 08:02:58 PM by Wobbly »
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but not the ability.

Offline ReloaderFred

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Re: Best ‘hold down’ die for swaging and priming
« Reply #2 on: September 12, 2019, 10:48:46 AM »
Flash holes are mostly punched, since it's so much faster than drilling.  They use a flat faced punch that pretty much removes a disc of brass the size of the punch, but the process also leaves a burr.  It's that burr that you're seeing flattened on the inside of the case.

The solution would be a hold down stem that is relieved in the center so it doesn't contact that little burr and move it over the flash hole.

Unless the burr completely blocks the flash hole, it probably isn't going to make much difference in a cartridge as small as the 9x19, though.  Unless you're shooting benchrest with the 9x19, I doubt it's going to show any difference on paper at handgun distances less than 50 yards.

Hope this helps.

Fred
After a shooting spree, they always want to take the guns away from the people who didn't do it. - William S. Burroughs

Offline painter

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Re: Best ‘hold down’ die for swaging and priming
« Reply #3 on: September 12, 2019, 03:57:48 PM »
Thanks for the correction re: punching vs drilling.
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Offline Wobbly

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Re: Best ‘hold down’ die for swaging and priming
« Reply #4 on: September 12, 2019, 07:46:49 PM »
Fred is right about the flash, or burr around the primer hole. When loading defensive ammo for myself, I chamfer the the inside of that hole with an RCBS Trim Mate motorized case prep center. RCBS has a drill bit that will knock that off.

Now that you have more stations, maybe one of them could be set up to deburr the case !?

Show us a photo of the "hold down". I might be able to make one with a hole in the center.
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Offline painter

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Re: Best ‘hold down’ die for swaging and priming
« Reply #5 on: September 12, 2019, 07:58:46 PM »
Thanks for the correction re: punching vs drilling.

Not to worry, I fixed it for you.   ;D
I really...really wish you'd stop that.

I hate it when anyone puts words in my mouth.

I'm considering deleting my account because of this.
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Offline Wobbly

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Re: Best ‘hold down’ die for swaging and priming
« Reply #6 on: September 12, 2019, 08:04:17 PM »
I really...really wish you'd stop that.


I stopped.
In God we trust; On 'Starting Load' we rely.

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Mature reloaders ask: What did I do wrong?

Check out my reloading equipment for sale CLICK HERE

Offline Clint007

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Re: Best ‘hold down’ die for swaging and priming
« Reply #7 on: September 12, 2019, 10:52:28 PM »
Thank you. And thanks also Wobbly for your offer, but I found a simpler solution to avoid squashing down the burr edges in my cases....

The problematic hold down die is an undersized expander ‘back up” die from Dillon used on the swage station On a 1050.  It’s designed to expand the case neck just after resizing, while simultaneously stabilizing the case during swaging.  They call it the back-up rod die,  as originally intended, It does not go all the way to the base of the case. And so I am using a 32 caliber version and setting it lower to make contact with the inside base since it’s diameter (.32) is smaller than the case ID.    The 9mm version wouldn’t go that far down obviously. 

I found last night that using a Dillon resizing die (without the depriming rod) is actually better and very effective.  It doesn’t need to be screwed down much to provide enough ‘back up’. Furthermore the timing of it is better, because when using the 32 caliber ersatz hold down die, it wouldn’t reach the bottom of the case before the swager rod was pushing up into the primer pocket. So the resizing die, making contact with the case mouth earlier in the cycle, is better. In fact I have one also now in the priming station now, to serve as a “hold down” die as the primer is seated.

C
Huh?

 

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