Lee Collet Die

[Buckskin]

I just got a Lee Collet die set for my 204 Encore barrel. Unfortunately I only had 6 empty pieces of brass that were not resized, so I used these as my testers, I sized 5 of them as directed, very easy to do and it makes the OD of the brass .002" les than my RCBS full length die.  The other die I used to make an overall length gauge with the last piece of brass. And I found out that I will never get to the lands with my little 32grain pill...

I loaded up a bunch of test loads with my full sized brass (so I could get more fire formed brass) and the the 5 neck sized brass and could not believe the difference in pressure that it took to seat the bullet.  Just the weight of the press arm was more than enough to seat the neck sized brass.  They seemed plenty tight, which suprised me, since the are only seated .130" into the brass.  My only concern is, will there be enough neck tension to create enough case pressure for correct powder burn?  I know I can get a smaller mandrel if needed.

[stimpylu32]

As long as the bullets stay were you seated them , it should not cause any problems as far as shooting these rounds , however here's were some other factors can come into play , like powder & primer choice's .

Some powders do better with a bit more time to burn , thus need more neck tention or even a crimp , yet some of this can be overcome just with a simple primer change , you will have to shoot the test rounds to see what works best for your rifle .

Clear as mud , right . 

stimpy   

[wncchester]

Let me suggest you do an experiment to learn just how much "neck tension" you get with both dies.  Measure the neck of two freshly sized cases with a micrometer, use a felt tip pen to mark exactly where you measured.  Then seat bullets in both and measure again,same place.  Pull both bullets and measure again.  No matter how much difference there was empty, I doubt you will see more than maybe a half thousant difference in the pulled necks diameter, maybe no difference at all.

What you will be looking at is the fact that once brass stretches passed it's yield strength it has no more elasticity.  Most necks will only have - maybe - one thou of elastic strength, any more stretching than that means nothing to bullet grip.  Meaning, it's likely you are getting all the grip you can use with the Lee die and it's probably giving you straighter necks too.  

The reason it's more difficult to seat in a smaller neck is you're using the bullet to expand the neck large enough to accept the bullet, that does NOT translate to more grip to resist bullet movement.

[Buckskin]

That does make sense. And I have no doubt that they have less runout, I don't know how they couldn't.  But Lee does recommend that you not use the Collet dies for hunting rounds.  My guess is that it's because they cause the neck tension to be less than standard dies and there is some concern of the bullet moving in or out of the brass.

[wncchester]

"Lee does recommend that you not use the Collet dies for hunting rounds.  My guess is that it's because..."

It's because no one "recommends" using neck sized cartridges for hunting. 

The concern is based on the reality that many (most?) guys will load up a batch of hunting ammo and go into the woods without ever checking to see if they will chamber.  FL sized ammo will (usually) work fine but some dufus types even screw that up.