shellholder design

S

skizzums

New member
just a question of curiosity. why do they make the shellholder with so much material above the rim? wouldn't it make more sense to have less metal above the rim so it can size closer to the rim? I hate the .15 at the bottom of the round that doesn't get re-sized. I am just wondering if there is a reason that I don't know for doing this. have you noticed, especially loading mag straight walled rounds that you can feel that little "bump" when inserting rounds into the chamber. I have been tempting to throw a shellholder on the lathe an take it down farther, but I assume the engineers at ALL the die companies probably have a reason for doing things this way

is that just the lowest they can go while maintaining the strength of the steel to pull the shell back out of the die?
 
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What's the "bump" you refer to on loading mag straight walled rounds? What cartridge is this?

Shellholders need to be robust and strong. Otherwise, they would not be able to pull a tightly gripped case back out of a full length sizing die without bending it. Some people have ground off too much of their shellholders only to have their lip bend up then off of a case rim that it too, gets bent out of shape. Shame on them for not putting enough lube on a case and using a press with a lot of leverage to push that case all the way into the die.

When a sheet of cartridge brass is shaped (coin, cup, draw, head, rim, bunt, neck and final sizing by another full length sizing die on the production line), it too needs robust shellholders at those stages after the one that puts the rim and extractor groove on the case head.

A few people have had special dies made that use a flat top shell holder to push a case all the way up into a die, then a levered rod pushes down through the top of the die against the inside on the head to get it back out. These special dies are used when the reloader insists on having the case body sized back down to its original diameters from the extractor groove forward. 99.9999999999% of all the other reloaders don't care if the case body diameter lessens from that pressure ring down to the extractor groove diameter; only a couple thousandths and not enough to realistically get concerned about.

Besides, that last .15" of the case head is the thickest part of the case. It's pretty hard to size down any significant amount anyway. And there's never been any real need to size it back down to its original diameter anyway.

You're the first I know of that's ever got concerned about it. Not a problem; that shows your intelligence to ask good questions about something you want to understand better. Thanks for asking.
 
That would ask another question one to do with the press you use .
I have a new Forster CO-AX and it does not use shell holders but instead uses a jaw system to hold different cases . It does not appear to be as thick as most shell holders . So I would think it would size MORE of any given case ?
 
Can you keep fooling with it and fooling with it?

Yes.

I have cut down the top of shell holders until the top breaks off while pulling the case out of the die.
I have cut the bottom off the die.
I have cut the bottom off a carbide die with a diamond cutter.
I have made my own co-ax jaws.
I have made my own co-ax jaw holder housing.
I have made my own dies.
I bought an innovative technologies collet die to get close to the web on belted magnums
 
Skizzums, are you loading belted cases? If so, talk to Clark more about the Innovative die made specifically for belted cases. I have one but probably don't have as much experience as Clark.
 
I had the same mini-bulge problem just recently on my 10mm reloads. While a push through die helps I also took some material off the shellholders top and inside to help slide the cases in and out. Works a lot better now.
 
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