The redding bushing thread in the Gunwriter's forum got me to wondering about something regarding Lee collet dies. Those squeeze the case neck around a mandrel for anybody unfamiliar with them.

I usually measure case necks for thickness consistency and sort out anything whose necks vary more than about .0015" around the circumference.

Noting how the Lee die works, has anybody ever measured a neck for consistency, take a fairly inconsisten one and run it through the die set up in some big honking crusher press, then measured again? I'm wondering if all that force might actually iron out the neck and produce a more consistent thickness all around? Am also thinking that much pressure might blow out the top of the die first.

Hmm, I might have to try this sometime to see. All I have is my decades old RCBS Jr press though, and not sure that could produce enough pressure.

All you're going to do is iron in some hellacious marks from the spaces between the fingers of the collet. And no, turning the case a little bit and making another pass won't smooth them all the way out, and you'll just be making more. The indicator needle of your neck wall checker will go bump bump bump bump as you turn the case on the mandrel. Not that I've ever fiddled with this......

Yeah... but it's the INSIDE of the neck that matters... not the outside, and since Lee runs the collet against a fixed diam. madrel the ID is usually very uniform (unless your brass is shot-up and springy... but that applies to all dies)... typically within .001". I don't really give a crap how my brass looks... it's how it shoots that is important to me. Don't know if you could iron out any OD inconsictancies... but that doesn't really matter if the ID is on the money.

And, just for the record... I've never seen "hellacious" marks from the collet... some small marks yes... but nothing crazy. If you're squeezing the collet hard enough to leave marks... then you're just being excessive.

The heavy marks came from heavy handed experiments.

My take on the OD/ID thing is they both have to be good for the centerline of the bullet to point down the throat the same way for each round.

+1!!!!



www.caribouhuntingripoff.com

OD may matter on a tight-necked bench gun... I haven't found it to be an issue on hunting rifles... but, I've only turned necks on a couple different cartridges. And, those were all loaded on Collet Dies...

Well I use collet dies too and I assure you I have some accurate hunting rifles that can show the difference between good and bad brass so processed.

"I'm wondering if all that force might actually iron out the neck and produce a more consistent thickness all around? Am also thinking that much pressure might blow out the top of the die first."

The excellant Lee collet neck die will not shift metal around to "uniform" necks, the compression is far to low for that.

The external vertical lines on the necks, when they appear at all, are shallow and harmless. The case neck's inner bore is excellant.

Significant over-pressure on the ram WILL blow the top plug out if the die. It's designed that way, to be the "weak link" so people won't bust the top off their brittle cast iron presses if they get overly ham-fisted. The reccommended 20# of lever pressure won't do it, but 50# is likely to strip out that aluminum safey plug. (Excessive lever pressure can and will break any press.)

The Lee collet die is unique and it does have a learning curve. Those not willing to try to understand how it works AND read the instructions will be better served with a more conventional neck die.

Funny how mileage varies...

What kind of hunting groups are we talking about? I don't mean the difference between outstanding groups and groups that wouldn't be perfectly suitable for practical hunting purposes. The mileage may not vary that much.

Did an experiment once with a super accurate factory 6mm Rem... started with 50 rounds of once fired brass... measured them all, weighed them, and sorted out the best 25. Then on the top 25 I deburred flash holes, trimmed to identical length, turned the necks, uniformed pockets... etc. The other 25 I just ran through the collet die and loaded up. Groups were indistinguishable... and the largest one was in the low .5" for 5 shots and average group size was in the high .3" range... in fact, I think the unpreped brass actually shot slightly better on average than the super tuned brass. JB did an article on this some time ago with a .223 and results were similar.

Now, I'm not talking about necks that aren't straight... I'm talking about necks that may vary slightly in thickness... or have "high spots". I think we'll both agree that if it ain't straight to start with... then accuracy will suffer.

Interesting.

My latest test along these lines was with a pretty accurate 308, a Model 700 VTR. Not as good as that 6mm though by any means.

I used two sets of once fired brass, all Lake City M852 match neck sized two strokes with a Lee collet die and then body sized with a Redding die for 0.001" shoulder bump. One set of brass had neck walls consistent to 0.001" or less, while the other set had between 0.0015" and 0.002" variation. The good stuff went ten shots into 0.8" while the "culls" went into 1.1".

I think highly accurate rifle will shoot just about anything well... some need a little more TLC in the brass dept. (among other things). I reckon if one wanted to squeeze that last .1" out of a rifle... then some meticulous brass prep might git-r-done.

I often use the phrase: "The last 10% of performance is 90% of the cost"... seems applicable here.

Excellent observation. I think that we sometimes can lose sight of what we are doing and spend money needlessly.

Different guns seem to be affected by brass quality and runnout differently. Over at LR Hunting a guy had a high buck, high quality long range rig. I forget the cartridge but he had to form his brass from a parent cartridge. He said after coming out of the die the brass had .025" runnout..yup that's 25 thousandths.
The result of feeding his rifle this lowly brass to fireform was that he was consistantly shooting .75" AT 300 YDS. In fact he said he could really not tell the diff between this horrible runnout brass and that which was fully fireformed. Kinda takes the "smoke" out of things a bit.

A good reason to sort brass by neck thickness. If the brass is made off center then neither neck turning or sizing with the Lee Collet will fix it

Doesn't answer the question at hand, but I use the Lee Collet dies nearly exclusively and have found it helpful for the sake of uniformity to run it through once, then turn the case 1/3rd turn and give it a second run with equal force.

Haven't measured results so I can't say that they're doing all I need 'em to, but the groups my rifle shoots and the brass life I get is enough proof for me.

I personally feel all the steps to neck consistency are about like a dog chasing his tail in most rifles. Concentricity is much more important. The lee collets will load very concentric rounds even with slight variances in necks IME. Out of Forester, Lee, RCBS, Lyman, Hdy, and Pacific dies that I own, the Lee Collets often produce the best ammo when it comes to concentricity. The Lee followed by the Redding body die is my favorite combo even for hunting rifles.

loder

I second that...

Concentricity is where it's at... if the center ain't in the center, then everything is out of whack... seems like a good metaphor for life aswell.

OK, and let's suppose the hole in the neck is perfectly in line with the body as the collet die is supposed to produce even with less than perfect brass. And furthermore suppose the bullet was seated right down the middle of that hole. Now when you place the round in the concentricity checker, with the support points on the case body, the bullet shows very little if any runout.

But also suppose the case necks are three thousanths thicker on one side. Does that not affect how the bullet is pointed down the throat? Thick side down, higher bullet. Thin side down, lower bullet and so on.

As much as I know it isn't true, it still seems to me that the barrel should be able to get a misguided bullet headed somewhat in the right direction.

This may be valid if the thick side is .005"-.015" thicker... but within reason (<.005")... I don't think the neck of the brass contacts the chamber (particularly in a factory chamber)... and the remainder of the unsized case should support the round... pointing it where in needs to go.

After I get the kids to bed I'll run some 7mm mag brass through the collet dies and take some before and after measurements.

Great thought though... it got me thinking... I can appreciate that.

The only problem I have with the Lee Collet/Redding Body Die combination (and I use a lot of them)


is that they do not let you set your bullet grip. Most of the Lee Collet mandrels are .002" below caliber and with springback you get .001" or so of bullet grip. This almost necessitates using a Lee Factory Crimp Die if you are against the front of the magazine with the bullet tips or have a compressed load. Now in my tests the LFCD has slightly increased velocity and slightly decreased group size but the crimp has to be chamferred off and eventually you will lose enough case length so that it will not work anymore.

You can order smaller mandrels from Lee for $5.00 each and I have done that in a couple of calibers. However, in corresponding with Lee they were adamant that increased bullet grip would decrease concentricity, that the light bullet grip was one of the secrets of such low runout. Maybe so, I haven't used them enough to be definitive about that. I do use a .280" mandrel in my 280AI with good results (so far). You can also spin a mandrel and take a little off with some abrasive surface, but my attempt at that was a disaster, YMMV.

With the bushing dies you can easily set your bullet grip by the bushing you use but you should outside neck turn to keep your concentricity in line. The phase I am in now is trying to get absolutely consistant bullet grip and release by steel wooling, scotchbriteing and using mica dust on the inside of the necks. If I use a Lee Collet with low bullet grip and then mica the inside of the necks then bullet grip is even less.

Yeah, the neck may not touch but then again it might. My Remington 700s have plunger ejectors which I *think* would push the case to one side. Twice fired neck sized only brass doesn't shoot to the same POI as brass that's been body sized for two thousanths shoulder clearance. Of course the body might run out of clearance first.

My beef with Lee's collet die isn't the idea, it's actually very clever. When they work they work quite well, I've experienced this myself. What I don't like Lee's indifferent finish and choice of materials. I'd pay $50 for one if it was built like a $50 piece of equipment. You know, a collet body made out of a good grade of steel with heat treatment so it's mouth won't peen after normal contact against the shellholder. Collet fingers whose edges aren't left sharp so the brass doesn't get distinct "gather marks" where the sides of the fingers close together. Collet fingers whose interior surfaces are polished so heavy tool marks aren't ironed into the case necks under even light sizing pressure. QC to assure that if only one mandrel is supplied it's at least going to be two thousanths smaller than the appropriate bullets. I got a 25 cal mandrel that my Starrett micrometer says is .257"! Neck tension anyone? Why not supply a set of them one, two and three thousanths smaller from the get-go? How about a little polish on the top of the collet fingers and the bottom of the plug they press against? The last 308 collet die I picked up had piss poor finish in this area. Gall-O-Rama.

You can order custom sized mandrels from them... I think they're only like $12. I turned .0015" off my 6mm Rem. die to up the tension a little. I agree though... one that was built with a quality finish would be nice... though I've used my 6mm and 25-06 collet dies literally thousands of times, and they're still going strong.

Plunger ejector shouldn't matter if the case body is left alone... I rarely bump any of the dimensions on my brass... unless they chamber stiff. Heck, I even use a .15" thickness washer over the brass to leave part of the neck unsized when running the 105 Bergers in the 6mm and the 115's in the .25-06... had a little lower ES when jamming bullets in the lands doing this. I have no idea why... it just works out that way.

I also agree that the plunger shouldn't have much of an effect when the brass is sized to snugly fit. I use my body dies to sort of PFLS if you will. A snug fit in the chamber will usually result in a gap around the neck. If the bullet is concentric with the body of a case that's sized for a particular chamber, it usually results in better accuracy IME. The only real improvement I've ever found in reloading is concentricity. Maybe the extra steps in brass prep works for some. I understand the need in tight necks, but in most rifles neck turning is pretty pointless.

loder