I just resized a batch of brass, and the necks are not concentric with the case body. They noticeably "lean" to one side. I have never noticed this before. I stuck a case in this die the last time I used it. Could the die or decapping pin be damaged? How can I tell which part of the die is the problem? Can I use a seprate neck sizing die to save this lot of brass, or is it ruined?

Some observations that I have made over the years:

I'll bet that your decapping pin has the neck expanding button near the bottom of the shaft (like most dies) and it is dragging in the case neck as it is pulled back.

Check the expanding button for rough spots and polish the button by spinning it in a drill using steel wool and metal polish. (Especially the tops and bottom tapered sections)

Lubing the inside of the case necks well before sizing helps also.

They should not "noticeably" lean anywhere. Something is very wrong here and needs to be corrected. Return the die to the MFr with a sample case that is noticeably leaned for replacment.

I'm curious....who is the manufacturer?

I have some Wilson knockout dies that do an excellent job of maintaining concentricity. Unfortunately I encounter the odd shoulder that gets blown out and the Wilson does not bump them back so they won't chamber properly. I started using a Redding body die which reforms the case but leaves the neck itself alone, only bumping back the shoulder. Then I use the Wilson neck die. Between these two the problem is solved, and the case remains concentric. Best wishes.

Cal - Montreal

The die is from RCBS. I've loaded over 200 rounds with it and never had a problem until now.

I don't use the exander.

If your cases were concentric in prior sessions then fix them by removing the expander completely and resize the cases without expander. That should fix the concentricity problem. Reinsert the expander and make sure it is centered in the die. Then, expand the necks by "pushing" the expander only into the necks with a very short stroke of your press, about a quarter stroke. They should be fine then. Next time lubricate the inside of the neck. Your expander ball has pulled them off center.

It is the case, not the die.

I have one R-P case that has .027" runout at the neck after FL sizing w/o the expander ball.

I have one unfired WIN case that has .006" runout after FL sizing. I have another that has no runout after FL sizing. Same die.

One thing I learned was that sizing with a body die seperately reduces runout over FL sizing in one step. Factory chambers are so loose that FL sizing creates alot of stress on the brass. If I size the body seperately from the neck, my runout is reduced by 75%.

On tight chambers, FL sizing does not create as much stress and the cases come out straighter.

It's neither the case nor the die! It's operator error!

Fired cases will conform to the chamber and if it's concentric the brass will be also. New cases or cases reformed from different parent brass will many times be eccentric as a result of the forming process. Firing them and then properly resizing will usually return them to concentric, then it's up to the operator.

One question I didn't answer for the original poster was how to check if it's a die problem. Size a fired case without the expander and check the concentricity of the case after sizing. Providing the die is adjusted per manufacturers' instructions, checking that case for concentricity will tell you if the neck is concentric. The shell holder should butt up against the base of the die, plus a ¼ turn to cause the press to "cam over" at the top of the stroke. That will full size the brass and enable you to properly read the production of the die. Sticking a case in an otherwise concentric die will have no effect on concentricity, that is a machining and manufacturing issue. Improper expander adjustment and use is usually the cause of eccentric necks.

Then how do you explain my .027" runout at the neck. I sized the case as you described.

Also, some cases exit my chamber with .0005" runout, and some with as much as .002" runout. Same chamber, how do you explain that?

Lube the inside of the necks, expander ball drag is the biggest contributor to concentricity problems.
bigbull

If you stuck a case then you removed the die to extract the case and re-installed the die into the press. Also you may have your decapper pin out to long and you have contacted the bottom of the case bending your decapping stem.Your die has to be straight in the press or you will have these problems. Put a flat washer on top of your shell holder, run it up and engage the bottom of the die. Keep up pressure on your shell holder while you tighten your lock screw down on to your press. Throw that RCBS lock ring away and order some Lee lock rings that have the o-ring to help center and align your die. You should once again be straight with the world.

quote:

Originally posted by Ralph Hyrlik:
........, how do you explain that?

Operator error!

Really,

One case emerges from the chamber with four times the runout than the next and you call this operator error?

Could you explain?

One case comes out of a PROPERLY adjusted FL die minus the decapping assembly with .027" runout and you call this operator error?

please enlighten us.

I was having some concentricity problems recently....certainly not as bad as .027" and traced it to a shellholder. Simply substituted a different one and had really low numbers again.
Re concentricity on the fired shells just out of the chamber....could they have been light loads with bad concentricity when they went into the chamber and didn't have enough powder to get a good "fire form" and striaghten them.
My guess is if you are sizing with a full length die without the expander in it and you are getting terrible runnout you either have a defective die body, defective shell holder, loose ram, or bad piece of brass. The bad piece of brass would kind of be a "one time only" deal but if you are having lots of problems it pretty much would have to be one of the others and trying other dies, and shellholders should begin telling the story.
If using expander spindles you think could be bent simply take them out and put on a dial indicator or roll accross a table and look for wobble.

quote:

Originally posted by Ralph Hyrlik:
One case comes out of a PROPERLY adjusted FL die minus the decapping assembly with .027" runout and you call this operator error?

please enlighten us.

No, YOU enlighten "US"! Explain how an inanimate object such as a concentric, fire formed case can be forced into a "properly" adjusted die (by operator definition,) be removed from the enforced reforming and then just arbitrarily push itself out .027". Not possible without an intervening cause. Was it annealed? Was something in the die? What is the common denominator?

I repeat, OPERATOR ERROR!!!

Well,

I just got back from the range. I took some new Norma cases that measured .001-.002" runout at the neck and fired them in my Savage. They all came out with .0005" runout at the neck.

I also shot some once fired and prepped R-P cases and they came out ranging anywhere from .0005" to .0025" at the neck.

Now Bob,

Pay attention.

Some of the cases are not concentric. They measure as much as .0025" runout at the neck! Did I open the bolt incorrectly? Perhaps I should have let them fly with a forceful ejection? No, I removed them carefully as to preserve the roundness of the case mouth for this test.

I resized the cases in a Redding body die adjusted to touch the shellholder and just slightly cam over. I then sized the necks seperately in a Redding Competition neck-die with a .247" bushing.

Normas came out .002" to .004" at the neck.

R-P came out .0005" to .004" at the neck.

Same rifle chamber. Same dies. Operator error?

NO.

Metal stress?

YES.

You see, Bob, not every case is concentric when it leaves the rifle's chamber. Some are some have measurable runout. When you resize them, you induce stress. The stress causes additional runout. I don't know why?

Bob,

I am careful. I pay attention to details. I adjust my dies correctly. Your explanation please.......

More data for Bob:

I took some once-fired Normas and sized them in a body die.

This did not induce any additional runout. It stayed at .0005"

I neck-sized them with a .254" busing. The runout increased to .001" in most cases.

I then necksized them with a .249" busing. The runout increased to .002" in a third of the cases, it remained .001" in a third of the cases, and stayed at .0005" for a third of the cases.

This tells me that the more you size, the more stress you cause, and the more runout you get. Sizing .008" in one shot produces as much as .004" runout, but doing that in two steps reduces the maximum runout by 50%- to a max of .002". I wish I had a .252" bushing. It would probably further reduced runout.

Where is the operator error?

The Head´n shouders cartridge headspace gauge,anyone using one of them,no .025"runout at the neck with it( to get this amount the shoulder should have been "crushed",without one it is only "guessing"/ .004" is 1/18 turn of the die.Operator not knowning hou much backing up the shouder(constant),difficult to argue with that,camming over 1/4 deeper when the die shell holder make contact,for a "standard chamber",1/4 turn of the die is.018",quite a resizing for cases.Getting near of .018"of headspace it is operator problem...

I know it sounds wrong, but the case came out banana shaped.

The more I see these posts on fancy dies the more I like my hornady dies. (yes I know they are the chevrolet of dies...maybe even the "saturn" of dies) Relaoded a batch last night that came out of my .308 auto loader with dinged up mouths that landed on concrete after being ejected. Not a one came out over .003" and most were right around .0015"--these were good old ordinary winchester brass bought in bulk. Not that my browing bar could probably tell the difference between .0015 runout and .006 runnout but why not try for the best?

I double checked my die. The decapping pin was bent. I replace the whole setup including the expander ball etc.. and resized the cases. They came out fine. I had to throw out out a few cases. The decapping pin hit the flash hole at an agle and bulged the brass in the primer pocket.

Ralph,

Have you checked the uniformity of the neck wall thickness? If there's more brass on one side than the other, the bullet will not go in straight, no matter what seater you use. I eliminate caes whose neck walls differ by greater than 0.0015 from one side to the other.

Jaywalker

Jaywalker, I completely agree with you, the only difference is that I do think that concentricity above .002" on the seated bullet IS discernible on a target depending on the accuracy of the firearm and the range at which you shoot. Whether it matters in a hunting rifle is another issue, but in Ralph's case there is more to it than that, far more.

I would have responded sooner but I couldn't tell from the tone of condescension if Ralph was asking for help or trying to "put me in my place". I certainly detest debates such as we see on a couple of current threads and I refuse to engage.

There is obviously a chamber problem in Ralph's case. Differences in neck wall thickness don't affect concentricity when the case leaves the chamber as the high spots are then on the INSIDE of the neck after expansion on firing. Its effect is significant in trying to produce concentric cartridges. There may be even more problems in the firearm if it's producing variably eccentric brass inconsistently as seems to be the case. Far more factory rifles have chamber problems that only good gunsmiths are able to detect. One way to check is to replace a fired case in the chamber at a different orientation. If it chambers easily, it's OK; if not, something is wrong with the chamber. Trying to get concentric brass starting with eccentric can be extremely challenging if not impossible. Also, there is no explanation for eccentricity of .027", something is radically wrong and I challenge even duplicating that one but I'm certain it's not the brass.

Another issue is the extent of working of the necks and whether the brass is annealed. Work hardened brass doesn't conform nearly as easily in the resizing since it's lost its ductility and elasticity which is a good reason for annealing necks regularly. I do it after any major case forming and every 4 reloads on all brass. If the necks expand significantly and are sized way down, they lose their ductility more rapidly than those not worked nearly so much.

The brass is NOT the problem. Cartridge brass is more or less made the same and has basically the same composition (70/30), it is changed by the treatment of it by either the manufacturer or us users and it's usually the user that causes ALL the problems, the only exception being brass which lacks uniformity in its walls. Our domestic manufacturers aren't nearly as good as some of the foreign ones although I've had some recent lots of Norma brass that competed or exceeded the worst lots I've ever had from Remington and Winchester, and at twice the price. This was notable in a recent lot of 300 WSM brass I used to expand to a wildcat.

Presses can also produce eccentric brass if the ram and machining for shell holders isn't square to the frame, plus you can get much 'slop' in the die boss from the threading. I went through many presses, about 10, before I found one close to being concentric. I finally went to a Forster Coax to assist in producing concentric cases and concentric seating more easily than futzing around with other presses, some of which were as much as .020" out of square. The crooked ones can be quite functional but if EVERYTHING is crooked to start, the process for concentricity is much more difficult.

I know there will be some that don't value concentricity and I respect that, but I do and pursue it vigorously. It does make a difference to me and I see it on the paper.

quote:

Originally posted by Jaywalker:
Ralph,

Have you checked the uniformity of the neck wall thickness? If there's more brass on one side than the other, the bullet will not go in straight, no matter what seater you use. I eliminate caes whose neck walls differ by greater than 0.0015 from one side to the other.

Jaywalker

I neck turn all my cases.

Bob,

There is no problem with my chamber. To prove it, note that every single Norma case came out with .0005" or less runout.

It is the POS R-P brass that came out with up to .0025" runout.

Same chamber. Same load.

The R-P brass is noticeably softer at the neck than the Norma. R-P brass comes out more concentric out of the sizer die than the Norma IF THE SIZING IS DONE IN ONE OPERATION. Sizing down .008" in one step results with up to .004" runout at the neck.

If the sizing is done in several steps, both Norma and R-P brass produce neck runout up to .002" or so. That is a big improvement. I hereby allege that the less sizing one does, the more concentric the round remains. In some cases, sizing improves concentricity.

It is the case that is 100% responsible for runout. Bags of brass contain cases made on many machines from many lots of alloy. They may be annealed the same, but that does not mean they are alike. You can take a bag of new brass, run the cases though an expand-iron mandrel and feel the difference in neck tension as you force that .224" metal slug through the necks. Same neck thickness, same anneal, what's different?

ALLOY COMPOSITION.

quote:

Bags of brass contain cases made on many machines from many lots of alloy.

Not true. OPERATOR ERROR!

quote:

It is the case that is 100% responsible for runout.

Not true. OPERATOR ERROR!

quote:

Bags of brass contain cases made on many machines from many lots of alloy.

Not correct. OPERATOR ERROR!

quote:

I neck turn all my cases.

Shouldn't have too. Much brass is available with less than .0015" variance in neck wall thickness. If it's worse than that, dump it. The walls of the body are the same relative variance. Turning shouldn't be necessary in rounds for a hunting rifle. Much better brass is available for benchrest.

YOU are the one with the brain and the ability to cure problems, not the brass. When any of us decide it is US that are in control and ARE the problem, we usually resolve those problems. Blaming inanimate objects doesn't cut it. "We" have the ability to reason and if it's a defective die or chamber, "we" have the ability to resolve the issue without blame other "things". Look at the common denominator first!

I'm through with this thread and won't engage in debate.