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Shims for Lee CND

Fast14riot

Gold $$ Contributor
I like and use the Lee Collet Neck Dies, not going to debate that. However I am trying to set up a 6mm Creedmoor CND to work for my 6x250. I need the collet to engage the shell holder a little sooner to keep it off the N/S junction and damaging the brass there. Those using shims, what exactly are you using on top of the shell holder? I need probably +.030". More than a comp shell holder can do.

20240701_184929.jpg
 
I like and use the Lee Collet Neck Dies, not going to debate that. However I am trying to set up a 6mm Creedmoor CND to work for my 6x250. I need the collet to engage the shell holder a little sooner to keep it off the N/S junction and damaging the brass there. Those using shims, what exactly are you using on top of the shell holder? I need probably +.030". More than a comp shell holder can do.

View attachment 1568366
Years ago I modified a LCND for a wildcat, I needed the same modification as you need.
I ended up using a dremel stone to hone the neck/ shoulder up. Its awkward, drop the shank of the stone tool through the neck from the inside and tighten it to the dremel. Grind, Stop, check, repeat.
PITA, but it works well.
 
As mentioned above, a washer with a large enough center hole to slip over your case. It will sit on top of the shell holder, and the collet will contact the washer. This keeps the case a little lower in the die. I’ve used this method to size 284 W necks in a stock 7x57 die.
 
46 -

Howdy !

The Lee collets are machined with generous amounts of oversize on their sidewall diameters. There is also some wiggle room to be had on the inside diam of the portion of the collet that accepts the case' neck. This presents potential opportunities to re-purpose the collet for a different case for your use.
For an example, I was able to use a .220 Swift collet ( and associated sleeve ) for doing neck sizing on a 6mm wildcat. The fairly long collet was shortened to the length needed for my application. The diameter of .220 Swift collet ( at the neck sizing end ) was generous enough to accept the wildcat's larger neck OD ( and sizing mandrel during use )
w/o the outside neck surfaces " dragging " on the inside of the collet. Final neck OD of your case would be a factor, in whether another cases's collet might be usable after modifying to accomodate your case' length.
The question:
Is there a collet for a different case that has a similar internal shoulder angle that is also longer on overall case side wall length ( than the 6 Creedmoor ).... that can be shortened to the length you want... This presents potential opportunities to re-purpose another cases' collet for your use....whether it be a .224" cal or 6mm case.

I'll submit that the internal shoulder surface of the collet does not need to be an exact match shoulder angle wise....with the angle on the case you want to neck size. The case will interface with the inside shoulder area of the collet at some point; as long as the collet's oal is properly shortened to the length you need. * The perhaps more-important angle is the mating angle on the outside of the collet used, with the angle of the mating surface on the inside of the die " sleeve " used. Interaction of these surfaces as the press and die are operated, are what drives the action of the collet petals pressing the case necks onto the sizing mandrel.

In your instance, potential use of a different collet will necessitate the associated use of a
" sleeve " that was manufactured for a 6mm case; and thusly is already machined to accept a " 6mm " mandrel.


With regards,
357Mag
 

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