Please help. I get less runout with my F/L die (<.001) than with my N/S die(.003-.005). Do you feel chamber fit is more important than runout? My feeling is that it is not.
What are your thoughts?

Whether it's a neck die or an FL die matters naught. The problem is in how much the die is sizing the neck and the relationship to the expander. The ideal sizing of the neck of a case fired in that chamber is under .010". A thou, or even two over that, is tolerable. Any more and the expander has to open the neck up too much to maintain concentricity.

Pull the expanders on both dies. Measure the diameter of the neck of a fired case. Size a case in each die and measure the necks. That should tell you quite a bit. You may have to return the dies to the manufacturer to polish out the necks. Alternatively you might need to measure and polish down the expanders. Their existence is probably the biggest single factor causing eccentric sizing. They are the reason for the existance of the bushing dies.

I agree with checking and polishing the expander buttons and also...HOW MUCH of the neck are you sizing in the neck die? ....many people prefer to size the upper part of the neck and NOT all the way down to the shoulder in neck sizing for accuracy...IF the brass is near the same wall thickness in the neck then that should give you more concentric sized brass and loaded ammo.....and I think the straight chamber helps more than straight ammo but a straight chamber with straight consistant ammo seems to be the best combo......good luck and good shooting-loading!!

While as a newbie to reloading (again, after 25 years), I've read that it does sometimes matter whether it's neck- or full-length sizing. On www.TheHighRoad.com, redneck2 answered a simlar question of mine with the following:

Quote:

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Problem with crooked necks comes from two sources. If you try to neck size only with typical dies, the case head may move in the shell holder. If the head is off to one side, it will bend the neck crooked.

Other is when the expander button is not round or off to the side (if the expander shaft got bent somehow for example). One brand of dies (RCBS?) has an O-ring that allows the expander to "float" and self-align. I've read that these can be added to other brands.

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I can't verify this, but it is consistent with other things I've read (need for O-rings, etc.) There's also a fair chance I've misunderstood.

Jaywalker

Nope, you didn't misunderstand. That's all very correct and true.



What's not been said is that friction from a very tightly sized neck or from lack of lubrication, can stretch the case unevenly and crooked as the expander is withdrawn.

I as so many others had the same dilemma and the same problem.
conclusions first: I threw away my nk. sizer.
I believe that chamber fit matters, but not as much as case body support when resizing. and since I started to belive in that I have gotten stright cases and straight shooting.
I work with Forster dies, because they were recommended to me. They drove me nuts for a while, but now I love them.
I polished the expander button, got a new pin that was straight and polished the neck of the die body. I took out the decapping pin, freefloated the die with an o-ring from the hardwarestore and put two more rubber washers under the topnut, so that the pin could really "dangle". Finally I adjusted the height of the expanderbutton until the cases came out straight. I also removed the spring from the shellholder and replaced it with a rubberband, to freefloat that as well.
If you have ceses with a big difference in neckwall thickness, so that one "side" is thicker than the other you may have to scrap them or neckturn them.
If you use a die with no expander (bushing die) and have, the above mentioned, variances in neckwall thickness, all you will accomplish is to transfer that difference to the inside, which in turn will be retransferred to the outside again when you place a bullet in the case. So that will do nothing for you.
caseBody fit... well I see it this way..: If headspace is minimum (.001" less than a fired nonresized case) how much can the case move away from center anyway?

Thanks folks! I have some new ideas to try at this game.
I bought a Hornady "Match Grade" N/S die with the hope I would get the runout problem solved. Yes, I did measure case neck thickness on the new brass.
Found 20 out of a 100 I liked.
The Hornady die has a bushing. How about dumping the expander button? I bought a bushing that matches the O/D of the neck of a F/L resized case.

Wayne,

If you are getting less runout with your FL die as compared to your Neck die, my first suspicion would be the chamber of the rifle. This doesn't mean that your chamber is "bad", most chambers are not concentric and have measurable runout (as measured by the fired case or cerrosafe cast). This includes any custom barrels short of a full-blown benchrest rig (the variance in chamber concentricity exists in a benchrest rifle, it's just so small as to be difficult to measure). You didn't say what kind of rifle you're shooting, but I can't emphasize enough the idea of PARTIAL RESIZING for most hunting and varmint rifles. This can go a long ways (not always--but often) towards "solving" runout and additionally makes case/neck wall variance less critical. I have a stack of neck sizing dies that I rarely use. Are you measuring runout by rolling the entire case on a concenticity gauge? With V-block/ball bearing? Any variance in the body of the case by resting the case on the V-blocks and spinning it will translate into a larger runout at the neck/bullet. I have been down this road before, and found that most of my hunting and varmint rigs (including my custom barrels) generally prefer partial resizing--as long as runout doesn't get too much out of hand. I won't even go into the pros and cons of neck turning as it pertains to runout.

Casey

I'll go with that. Partial resizing is what I call well adjusted FL resizing and it works.
Adjust the die so that it just bumps the case shoulder and set it back about .001" ( You need a stoney point headspace gauge) If you "FL size" like that, you'll have around 00.1" play lengthvise, how much away from center can the round get with that little play.

Hey Folks! I don't have the stoney point. But what about taking out the expander ball? The Hornady has a bushing.
I must not understand. The fired cases have almost no runout when I measure on the vee blocks. To me, that tells me the chamber is close to true. It's when I resize that I have problems.
Please don't get tired of me asking, I've been reloading less than 2 yrs.
Is the concensus to dump the N/S die? Is there any way to partial F/L size without using the stoney point gauge?
Thanks for the patience!
--Wayne

I always get better runnout with a full length die. (But I don't have the fancy match grade neck dies with bushings). The reason I BELIEVE the runnout is better is the full length die has a better grip and alignment of the case during the whole process. With most neck dies your sizing operation is taking place inches away from a sloppy shell holder. Is it any wonder something can move a few thousandths of an inch?? As an examole .004" runnout is the thickness of a piece of computer paper--it certainly doesn't surprise me that you can get out of whack that much with a neck die.
If you want to save time and get perfect neck sized ammo buy the lee collet die. Otherwise use a full length die. Runnout is "overated" as an accuracy problem anyhow. Find a load your barrel likes and that .004" will be straightened out by that 50,000PSI trip down the 24" long barrel EVERY TIME

Thanks. I needed to hear that!

Hi Wayne. Sorry.. But I do not agree. Run out is a problem. If you ask me. I do agree on using fl dies for the better hold while resizing.
If you do not have a headspace gauge, (Stoney point or any other brand) my best advice is: Get one. It's not expensive and a good investment for precision reloading.
If you want to find out for yourself, if runout matters.
try this: select say 5 rounds that are straight, and 5 bad ones. Fire the straight ones at one target and the other 5 at another. Them go measure the spread and compare.
Be sure though that you have eliminated as many other variables as possible. You know... same trimlength, same case, same bullet bla, bla....

Have fun

I'm with Niels. Runout matters. How much it matters depends on what you expect out of your rifle. If a loaded cartridge has significant runout, the bullet will get started down the bore crooked. Yes, 50,000PSI will shove that bullet through the bore, but what happens to that bullet in the process? It gets swaged into deformity. Try this test with an accurate rifle for which you have worked up some very accurate loads. Go to the range on a calm day, unless you are very good at doping wind (trying to eliminate variables) and fire 2 ten-shot groups. One of these ten-shot groups, however, you will be shooting with bullets that you've dropped to the concrete floor from over your head before loading. If you can't see a difference in group size with good bullets and those that have been damaged from dropping them (whether or not you can see damage), I would tend to blame the shooter for all differences in group size.

I guess I'm not up to all the modern things in reloading such as runout,turning necks or weighting cases for factory rifles,etc. I use wilson dies and don't worry about run out. May ream the inside of the neck once in awhile. Do turn necks for my tight neck rifles. Use a body die or Neil Jones custom dies just to bump the shoulders back. I have found over the years that alot of problems happen from the expander ball even when lubing the inside of the neck. You just stretch the case and if it gets the neck from being straight then the case can be off even the press can be off don't need to be a genuis to figure that out. I think JLC does a good job of converting regular dies to use a bushing or get he Redding type S full length die. Or you can send some fired cases to Wilson and he will make you up a neck sizing die. I'm about to send some dies off to JLC. I kind of want my round to fit the chamber more than worrying about run out. In one of my weaker moments I even when so far as to index cases. So kind of been there done that. When you get into a custom tight neck rifle then you can see more of the changes you make to a case such as neck tension etc or if you can shoot like Tubbs or Boyer. I think you have to match the level of your shooting to your rifles and reloading. I've got a custom 300wsm and I've got one case thats been fired 6 time with a full load of N165 and it's just been in a wilson dies. With the factory barrel I got 8 firing before it when to a body die. For the ones that believe run out is impotant go for it what ever works for you. Tom