Turn down Lee collet neck sizing die? *update/fixed*

[ExtremeX]

SEE POST #9 for Fix / Update

[Mike402]

I had the same exact issue - stock one was fine for /308, but I wanted tighter neck tension on my .223 since I didn't want to crimp. My solution was to order a custom undersized mandrel from Lee. It was like $12 w/ shipping & got to me in about 10 days. Problem solved...

[ExtremeX]

Do you know what size mandrel you ordered?

I still have to pull mine out of the die and measure it, but id like to compare for curiosity sake.

[farnorcal]

I don't know what I'm talking about , at first I thought you meant the expander ball.

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[Mike402]

Do you know what size mandrel you ordered?

I still have to pull mine out of the die and measure it, but id like to compare for curiosity sake.

Here is the description from my order:

Custom Undersized Mandrel
Options: cartridge: 223 Rem
Thousandths: .003

This gives me .003 neck tension right out of the box (of course after adjusting the die properly)

[FLIGHT762]

I had the same exact issue - stock one was fine for /308, but I wanted tighter neck tension on my .223 since I didn't want to crimp. My solution was to order a custom undersized mandrel from Lee. It was like $12 w/ shipping & got to me in about 10 days. Problem solved...

Here is the description from my order:

Custom Undersized Mandrel
Options: cartridge: 223 Rem
Thousandths: .003

This gives me .003 neck tension right out of the box (of course after adjusting the die properly)

O/P, listen to Mike, he knows what he's talking about. I also use a couple of Lee Collet dies. I have polished the mandrels down to get a little tighter tension, but as Lee warns, you shouldn't polish it down more than .001".

My Collet dies work great, but if I was doing this all over, I would take Mike's advice and contact Lee and buy the separate, undersize mandrel.

You can mark the smaller mandrel with a sharpie and switch out the mandrels, on different brass as you need to.

[dreyna14]

You could use some fine grit sandpaper and chuck it in a drill if possible. Use a good micrometer and work slow. Removing .001-.002" should be easy and still maintain good surface finish.

[ExtremeX]

Ill probably order a new mandrel... but I only need to polish it down .0005 to .001 anyways. I typically like to run about .001 to .0015 neck tension for my bolt guns.

Right now its just way too light. Hopefully Lee has something just incrementally smaller, if not its getting polished.

[ExtremeX]

Fixed it… and it’s better than new.

Out of the box the Lee mandrel wasn’t in the best shape… it varied in size with the blue area being the thickest (thicker than the green area where the mandrel makes contact with the case neck)

Used:
600 grit sand paper
0000 steel wool for polishing
Drill press



The red area I had to wrap some paper to protect the head of the mandrel (from the drill press chuck) which is there to prevent the mandrel from falling though the die.

After sanding and polish it was even more consistent than what came from lee. Neck area finished at 0.2220”. Blue area was reduced to .2218 so it doesn’t rub the neck after sizing. Process removed all the machine marks from Lee which you could feel with a finger nail. Red area wasn't processed, it isn't as smooth, it doesn't comes out in the photo, but its a noticeable difference.

Indexed the case and tested neck tension. Perfect .002” tension on my cases. Very happy with the results.

As a comparison my RCBS FL sizing die puts about .0035 neck tension. Before processing the Lee die, it was extremely easy to push the bullet into the case after seating it. Now you really have to lean into it.