Home Forums Reloading Big Game Rifles The famous Lee Collett Neck Dies.....

Here's the deal. I've been making concentric ammo with Redding bump dies and Redding Nk dies for a long time. But....being the handloading loony I am, I finally got a around to trying the Lee Collet dies that I bought.....two years ago....

243W die: It won't size enough neck tension--I can almost insert the bullet by hand. The word is to turn the mandrel down a bit to get proper neck tension ( with sandpaper, emery cloth, etc). What grit are you starting and finishing with? How much do you think I should remove? In other words how much neck tension should I be looking for in a hunting round?

270W die: The neck walls are "extruding" into the slots on the cone. Am I putting too much pressure on the press? Or do I need to hone out the edges of the slots? If so, what are you guys using to accomplish that?

I'm not even gonna try the 257R or 30-06 dies until I figure out the first two.....

IIRC they try to size the neck ID to be .001" under the bullet diameter, that doesn't give a really tight hold on the bullet and thin necks can exacerbate that. You can size down the mandrel or Lee sells .002" undersize mandrels for $4 if you don't want to sand the original down.

https://leeprecision.com/home.php?cat=19098

By neck walls extruding, do you mean you're seeing four actual longitudinal ridges around the exterior of the neck? If so then yes, that's way too much pressure. I've never seen the need to smooth the inside of the collet fingers although the exterior of the collet area can benefit from some polishing with 600 or maybe finer grit and a thin film of viscous lubricant like lithium grease.

Hopefully with his permission (or forgiveness ) here is mathman's write up on how to adjust the dies:


Originally Posted by mathman
The first thing I recommend is to ignore the instructions supplied with the die.

The second thing I recommend is to ignore whether or not the press you're using cams over at the top of its stroke.

The die squeezes the neck onto a mandrel, so for a given neck thickness there is a finite limit to how much sizing you can achieve. This die will need adjustment to suit different thicknesses of brass.

Raise the press ram to the top of its stroke. Thread the die into the press until the bottom of the sizing collet (not the die body) just touches the shell holder. Measure the neck OD of a piece of brass.

Run the brass through the die using a full press stroke. It should take no effort since if you're set up as described the die has done no sizing. Turn the die into the press about 1/4 turn. Run the brass in again. You probably won't feel much sizing going on, but give the neck a measurement just to see. If it's still nothing, screw the die in another 1/4th and try again. You'll may start feeling a bit going on as you work the press handle, and if so you'll be able to measure a little sizing taking place.

Rinse and repeat using 1/16th turn in increments for the die. You'll feel increases in the force required for the sizing stroke. Since you're measuring the neck after each pass you'll eventually find two increments where the neck didn't get any smaller. NOW STOP TURNING THE DIE INTO THE PRESS. Remember you're squeezing the brass against a solid steel mandrel which isn't going to give, so even if the press stroke didn't feel like it took very much force the neck is as small as it's going to get.

There's a learning curve to the die, but it isn't hard.

I like to run cases through the die twice, spinning the case about 1/3 turn (rather than the 1/2 turn in the instructions) between passes. This means the parts of the neck that were under the splits in the collet fingers on the first pass will get hit on the second.

The directions that come with the die do not work, period.

Below is how to set the die up correctly. As to polishing the mandrel, I use a file, followed by 120 grit paper & I make sure there are no edges on the very bottlom of the mandrel that will catch the case mouth as the mandrel enters the neck.

For my use, I want the case to have .003" total interference fit to the bullet, so for a .224 bullet, I want the neck ID to be .221".

You can polish the die fingers inside & out with a scotchbrite pad & make sure they are well lubed.

Here's the correct procedure for setting up the die & some other info from another forum from some years ago that I have kept. Hope this is clear & Good Luck.

MM




"Using The Lee Collet Die.
I started using Lee collet dies when they first came on the market and have found that they are very good for the purposes for which they were designed .
I have found that there is a lack of understanding of how to use the die properly and as a result people fail to see the advantages that the die can deliver over standard neck sizing dies.
This is not the fault of the product , it is just a lack of understanding of how the die works and what it will feel like when you operate the press correctly.
Standard dies use a neck expanding ball on the decapping rod and size by extruding the neck through a hole and then drag the expander ball back through the inside neck.
The collet die achieves neck sizing by using a split collet to squeeze the outside of the case neck onto a central mandrel which has the decapping pin in it’s base .
One advantage is that there is no stretching or drawing action on the brass.
The inside neck diameter is controlled by the diameter of the mandrel and to some extent by the amount of adjustment of the die and the pressure applied to the press .
This results in less misalignment than can occur in standard dies because of any uneven neck wall thickness in the cases .
Cases will last longer in the neck area and require less trimming. If cases have very uneven neck wall thickness then this can cause problems for the collet die they definitely work smoother and more accurately with neck turned cases but it is not essential.
When you first receive the die unscrew the top cap and pull it apart check that everything is there also that the splits in the collet have nothing stuck in them then inspect the tapered surface on the top end of the collet and the internal taper of the insert to make sure there are no metal burs that might cause it to jamb.
Next get some good quality high pressure grease and put a smear onto the tapered surface of the collet .
Put it back together and screw it into the press just a few threads for now . The best type of press for this die is a press of moderate compound leverage that travels over centre .
Over centre means that when the ram reaches its full travel up it will stop and come back down a tiny amount even though the movement on the handle is continued through to the stop .
eg. is an RCBS Rockchucker.
This arrangement gives the best feel for a collet die sizing operation.
Place the shell holder in the ram and bring the ram up to full height then screw the die down until the collet skirt just touches on the shell holder , then lower the ram .
Take a case to be sized that has a clean neck inside and out and the mouth chamfered and place it in the shell holder.
Raise the ram gently feeling for resistance if none , lower the ram.
Screw the die down a bit at a time .
If you get lock up ( ram stops before going over centre) before the correct position is found then back it off and make sure the collet is loose and not jammed up in the die before continuing then raise the ram feeling for any resistance , keep repeating this until you feel the press handle resist against the case neck just at the top of the stroke as the press goes over centre and the handle kinder locks in place .
This takes much less force than a standard die and most people don’t believe any sizing has taken place .
Take the case out and try a projectile of the correct caliber to see how much sizing has taken place.
If it’s still too loose adjust the die down one eighth of a turn lock it finger tight only and try again .
Once the die is near the correct sizing position it takes very little movement of the die to achieve changes in neck seating tension .
This is where most people come undone , they move the die up and down too much and it either locks up or doesn’t size at all .
It will still size a case locking it up but you have no control over how much pressure is applied and some people lean on the press handle to the point of damaging the die. A press like the RCBS Rockchucker , that goes over centre each time gives you a definite stopping point for the ram and the pressure that you apply .
There is a small sweet spot for correct collet die adjustment and you must find it , once found , how sweet it is ! Advantages : With a press that travels over centre it is possible to adjust the neck seating tension within a very limited zone. No lubricant is normally required on the case necks during sizing .

If you still cant get enough neck tension to hold the bullet properly for a particular purpose then you will have to polish down the mandrel.
Be careful poilishing the mandrel down and only do it a bit at a time as a few thou can be removed pretty quickly if you overdo it.
You can't get extra neck tension by just applying more force. The amount of adjustment around the sweet spot is very limited and almost not noticable without carrying out tests.
For example , to go from a .001 neck tension to a .002 or .003 neck tension you would be talking about polishing down the mandrel.

There are some other advantages but I will leave you the pleasure of discovering them .
One disadvantage that I have found with the collet die is that it needs good vertical alignment of the case as it enters the die or case damage may result so go slowly.
Also some cases with a very thick internal base can cause problems with the mandrel coming in contact with the internal base before the sizing stroke is finished.
If pressure is continued the mandrel can push up against the top cap and cause damage . If you are getting lock up and cant get the right sizing sweet spot, then check that the mandrel is not too long for the case you can place a washer over the case and onto the shell holder and size down on that.
It will reduce the length of neck sized and give the mandrel more clearance. If it sizes Ok after adding the washer then the mandrel could be hitting the base.
This is not a usually problem once you learn how to use them .
The harder the brass is the more spring back it will have so very hard brass will exhibit less sizing than soft brass because it will spring away from the mandrel more. If this is happening to excess then use new cases or anneal the necks.
Freshly annealed brass can drag on the mandrel a bit in certain cases because it will spring back less and result in a tighter size diameter.
I have experienced it. I always use some dry lube on the inside and outside if I get any draging effect . Normally you dont need lube.
I make up a special batch 1/3 Fine Moly powder. 1/3 Pure graphite. 1/3 Aluminiumised lock graphite. Rub your fingers around the neck and It sticks very well to the necks by just dipping it in and out and tapping it to clear the inside neck . After a few cases it coats up the mandrel .
Other dry lubricants would work also.
Use the same process for normal neck sizing also.

I noticed a definite improvement in the accuracy of my 22-250Rem. as soon as I started using a Lee collet die instead of my original standard neck die.
Readers are encouraged to utilise the benefits of responsible reloading at all times. Although the author has taken care in the writing of these articles no responsibility can be taken by the author or publisher as a result of the use of this information."

Thanks to both of you. Jim, I'm glad you saved mathman's instructions--I now recall those!

MM, when you use a file to polish, are you chucking up the mandrel and holding the file against it?

Alpinecrick,

I don't know if this will help you or not, but I do notice a difference in neck tension between freshly annealed cases and cases that have been fired a few times and are due for annealing. I'm wondering if the necks on the fired cases are a little more work hardened and are springing back a little after being squeezed onto the mandrel. They definitely don't grip the bullet as tight. Maybe try annealing a few cases and then sizing them to see if they grip the bullet a little tighter.

Thank you for sharing this information. I thought it was very helpful.

I used the Lee Collet Dies for many years for my 308/30-06 ammo. I was happy with them for a long time. Eventually I got tired of the occasional FL resize to bump the shoulder back. Also had issues along the way with loose bullet tension.

I've finally put the Lee Collet Dies on the shelf.




My current setup is really working well. It's the Forster Bushing Bump Neck Sizing Die, paired with Redding Competition Shellholder set.

The shellholders allow for precise and consistent shoulder bump to match headspace. The bushings can be swapped out to accommodate thin/thick case necks. Also the bushings can be backed out a bit (half turn or so) to leave the bottom of the neck un-sized and a perfect fit to the neck area of the chamber.

With this setup, only minimal case lubing at the neck/shoulder is needed, I'm using Imperial wax.

Your experiences are similar to my journey as well. Was a neck sizing true believer for a long time until neck tension and chambering issues kept rearing their ugly heads. So, I went back to FL sizing and simply using the Redding competition shellholders. Rounds chamber now and my runout & accuracy are fine. I suspect I should move the bushing route (have it only for 308--my M1A) but am too dumb, fat & happy.

I have been asking about the Forster bushing bump neck sizer die around here for well over a year with basically zero replies. It's great to see someone useing these and it's appears there at least in your case working as I suspected. Thanks for your post and I look forward to trying these. I'll also use the Redding competition shellholder set with them when I give it a go. Imperial wax is the only way to go IMO 😁

If you don't mind my asking are you turning the case necks or no? Thanks



Trystan

The Redding bushing neck sizer only sizes about half of the neck, which is why I prefer the Lee. If you're experiencing loose necks with the Lee, all you need to do is order an ever so slightly smaller mandrel from Lee.

I'm not MM but I've polished quite a few collet die mandrels so maybe this'll help. I don't use a file, I use a strip of 600 grit auto body sandpaper cut about an inch wide and 3" long. I first measure the mandrel with a micrometer (very important) then chuck it in my cordless drill with the decapping pin end in the drill. The part that sizes is about a half inch below the top so that's the part you need to get right. I put a couple of drops of oil on the mandrel then wrap the sandpaper around it & hit the drill for about 15 sec. Measure and keep doing it until I've taken .001" off. I then turn the mandrel around in the drill and polish the bottom end down the same amount but it's not as critical as the sizing area, you're just doing this so the case doesn't drag coming out. I size a case with the turned down mandrel and if it gives me enough neck tension I'm done, if not then I repeat and take another .001" off.

It's pretty easy, even I can do it.

Mathman's instructions for setting up the die are good, the instructions that come with the die itself are useless and will lead to nothing but frustration.

On rounds that I use the collet die for I always use a redding body die set up to bump the shoulder .002". Neck sizing alone with lead to frustration after a few shots, I always bump the shoulder with every sizing. If I'm using a conventional full length die I set them up to bump .002" also. Every cartridge I use with a collet die I also have a redding body die.

Feel free. Being an old academic, I certainly don't mind receiving more citations in the literature.

tag

No I'm not turning case necks. I bought four different bushings that should cover my needs in the 308 and 30-06.

Redding Bushing Dies have been working for me up until now, don't see a need to mess with all that. If I were to change, Whidden would likely get my money.

Anneal the necks and the Lee collet die works just fine.

Yes, neck annealing definitely helps with the Lee Collet Die.

I've done a bunch of them at the table with a torch.

Damn. You wear a Glock while annealing cases? Wouldn't a S&W be more appropriate??.

Well, if I'm awake, I'm probably wearing it.

AND....a belt with suspenders. Major fashion faux pas. 😁