Neck Sizing Die Adjustment?


September 13, 2003, 01:02 AM
I recently purchased, and am using for the first time tonite, a Forster Neck Sizing Die instead of my regular full-length sizing die. I use a Dillon 550B. The directions for the Forster die said that there no adjustments necessary and that the die should just be screwed all the way down to the

I noted that the sizing die, as set by the factory (and verified by me) sized the neck a little bit smaller than spec.

My Speer reloading manual says that the outside neck diameter should be 0.3435" (I am assuming this is the sized dimension).

My die takes the outside neck diameter down to 0.3390", which is smaller by 0.0045".

BTW, I am using Federal Brass currently and will be using some just-purchased Lapua during my next reloading session.

When I seated the Nosler 168 J4 I noticed that it usually required somewhat more force to seat. I also notice that some of the bullets had a teeny amount of copper shaved up to the neck of the cartridge.

I'll take grand guess and assume this is not normal. To correct this, should I back out the neck die until it sizes to spec or is this die only able to size the specific area on the cartridge if it is screwed in all the way (which is what I am guessing). If so, is this die possibly out of spec?

Edited to add: Hmmm. I didn't think this would be such a stumper. I'm also going to e-mail Forster at

Nearly a newbie.

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September 13, 2003, 01:39 PM
Have you champhered the case mouth? Most dies size the neck too small, then bring them back to size when the expander ball is dragged back thru the neck, incidentally tweaking it out of alignment...:barf:

If the pointy end of your deburring tool doesn't do a good job, try a case mouth reamer from K&M or Holland for a longer, smoother angle on the cut.

Or you can switch dies to a Lee Collet (inexpensive) or Redding bushing (easy control of amount of sizing). :D Still need to champher it tho.

Good luck,

Nero Steptoe
September 13, 2003, 02:42 PM
Since brass thickness varies from brand-to-brand, and according to the number of times brass has been used, I'd rely on the i.d. of the neck after resizing, rather than the o.d. The i.d. should be a couple of thousandths under the o.d. of the bullet.
I also use and recommend the Lee Collet Die. You don't need to do any expanding with that die, so the brass is worked less.

September 13, 2003, 07:22 PM
I got ya.

I used the chamfering tool on all of them but after the first bullet got skinned I found I had to chamfer them more than I was used to. It is still undersized from spec after sizing and after seating and crimping by the dimensions above.

So, what y'all are telling me is that I don't really have any adjustment ability on this die. From the diagrams, if I back out the die, I also back out the lower part of the neck which means it doesn't get resized.

Also, when I up-stroke the press, the expander ball really grabs hold of the inside of the case and I have to use some force to get it to break through the neck.

No word from Forster over the weekend just yet.

Thanks for your help.


September 14, 2003, 06:46 PM
Def use a dry lube on the expander if it hanging up on the upstroke you can throw out the shoulder if you don't.If you use any other lube your prob gonna have to clean the brass or powder will stick to the sides of the brass.On the dies I use Redding comp dies and your can get different size bushings for neck tension so I couldnt really help ya on that.

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