Concentricity - What to do when your seating die is messing things up

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Hi - I've done a bit of searching on CGN and elsewhere to see what can be done about improving concentricity; the most helpful thread so far is at https://www.canadiangunnutz.com/forum/showthread.php/1964318-Concentricity-tools-opinions/page2, where it indicates how to proceed to figure out where you're getting alignment/concentricity issues.

First: setup: 6ppc, .263 neck, necks turned to 0.0087 (+/-), Redding body die, Redding Type S Neck Bushing Die, Redding Competition seater, Lee Challenger press, and Berger projectiles.

Measurements: taken at case neck and near ogive, on a tool where the case is supported near the base and just below the shoulder (similar to the Sinclair tool).

Issue: With my last set of handloads, after seating, the average T.I.R. on the neck was 0.0016, but the average at the ogive was 0.0056. There were some rounds which were showing as much as 0.008 T.I.R. at the ogive, yet the measurement at the necks were all between 0.001 and 0.002.

(Note: I'm assuming that T.I.R. is the max-to-min deflection measurement, meaning that the ogives were oscillating on average between 0.0028 "up" and 0.0028 "down" (half of 0.0056); please correct me if I'm using the wrong term here.)

After firing the loads described above this weekend, I've measured that brass's concentricity:
- after firing (average TIR = 0.0008) (not measured last prep cycle),
- after body sizing (average TIR = 0.0007) (not measured last prep cycle), and
- after neck sizing (average TIR = 0.0016) (same value as previous prep cycle).

For comparison, a recent batch of 223 reloads was measured to have an average of 0.0025 on the neck, and 0.0032 at the ogive, so I don't -think- my methods are terrible.

Given that there seems to be room for improvement in the seating phase of the process, I'm wondering if there are any suggestions that could be used for getting the bullets seated a bit more inline with the cases and reducing the measurement somewhat. I think that I can live with the average run-out, but I do not like the extreme values (out of 25, 2 and 4 were 0.008 and 0.007, respectively).

As I'm doing load development right now (different charge weights), I can't speak to how concentricity may or may not have affected group-size at this point - I can track that down the road, once a load is settled on.

Ideally, I'd like to incorporate promising-sounding feedback into the next reload cycle - I will report back on what gets tried and how it worked.

Note: When seating bullets, I do the "seat, lower ram, turn case 180, raise ram, lower ram, NEXT!" routine. I've recently read suggestions of doing this in 2 x 120 degree turns, rather than 1 x 90; not sure that would help much, but maybe?

As always, any and all feedback appreciated (including the not-unlikely "Shaddup and just shoot already...").

Thanks in advance.
 
Assume neck tension of 1 thou actual.. if more, try less. If you haven't annealed your necks, that is a very good thing to do on a regular basis.

if the runout continues, try a different seating stem or a different type/brand of seater like a Forster... or go all in and get a Wilson seater and arbor press.

Ultimately, you need to test the ammo on target and determine if runout is causing any issues.

If I can help with stuff, just let me know Thanks

Jerry
 
Below is the link on seating die testing from the now closed down "The Rifleman's Journal" website that covered many competitive shooting and reloading subjects.
The link is in Adobe Acrobat .pdf format so I printed the results from the artical if you do not have Adobe Acrobat on your computer.

Reloading: Seating Die Runout
Seating Die Induced Runout - A Comparison
by Germán A. Salazar

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwjxnvrdt87nAhUmmXIEHRwAAzYQFjAAegQIBhAB&url=http%3A%2F%2Fwww.uniquetek.com%2Fstore%2F69629 6%2Fuploaded%2FReloading-Seating-Die-Runout.pdf&usg=AOvVaw0PTrUzbIFGXpTquMkz6CtT

The Rankings
And now, the moment you've been waiting for...

#1 - Redding Competition Seating Die (sliding sleeve type, threaded die)
The Redding, which I expected to finish high, did what I thought couldn't be done - it
produced rounds with an average runout that was less than the average case neck
runout of the brass used. In none of the ten rounds loaded did the Redding increase
the runout; it either held exactly the same or it decreased. The Redding, with an
Average Runout Change of -0.0003" is the winner. The negative sign, of course,
indicates a reduction in runout.
However, it's important to note that we're using a mathematical calculation that gives
a result that is smaller than the precision with which we can measure runout, so take
the numbers as what they are - smaller than we can reliably guarantee and more of a
ranking indicator than an exact measure of probable runout results. This applies to all
the dies.
#2 - Wilson (chamber type, for arbor press)
I expected the Wilson to come out on top, given it's long-standing reputation as the
best seating die and its near universal use in Benchrest shooting. It didn't quite work
out that way, but the Wilson was very good, with only three rounds increasing runout
and an equal number decreasing, the remainder were zero-change. Wilson Average
Runout Change: +0.00015".
#3 - RCBS Standard Die (standard threaded die)
I expected the RCBS to be dead last, maybe by a big margin; was I ever wrong! I
was really surprised, quite pleasantly, by the RCBS die's performance. Three runout
increases, an equal number of decreases and four zero-change made for a very
creditable score. RCBS Average Runout Change: +0.00025".
#4 - Vickerman and Hornady (tie) (both partial sliding sleeve, neck only, threaded
dies)
These dies share a lot in common, being of universal use for a given caliber, in this
case, .30 caliber. You can seat bullets in anything from a .300 Savage to a .300
Winchester Magnum with these dies as they just capture the neck of the case in order
to align it with the bullet. However, as your Economics professor taught you, there is
no free lunch. That universality of application reduces precision, though certainly not
to a level that would render them useless. With more increases in runout than
decreases, the Hornady lost ground. The Vickerman had a lot of zero-change rounds,
but increased 0.002" on a couple and that really hurt it's average performance. So,
the Hornady and Vickerman with an Average Runout Change of +0.0006",
bring up the rear - very much to my surprise. These are very useful dies, however
and let's keep some perspective, with an ARC of about half a thousandth, I wouldn't
be concerned about using them for Highpower match loading.

Update - November 7, 2009
Below is a picture of the targets fired with the ammo loaded for this article (it only
took two months to find a free day for this!). All firing was done at 100 yards, prone,
iron sights with the CSS RT10 Tubegun. All targets have 10 shots, the same 10 that
were in the runout test for each die. I shot the Hornady die ammo first and the group
was a bit low, so I made a small elevation change for the remainder. The RCBS die
ammo certainly looks like the worst, and the Redding the best, but I suspect things
might shift around a bit on a rerun of the test. Conditions were ideal for this testing
and I'm satisfied enough with the way I shot that I don't plan to repeat it. I think all
groups were fired in a consistent manner, none being better ot worse than the others
in terms of overall execution. You can click the picture to enlarge it for more detail.
The targets is the NRA 100 yard Smallbore target, with a center X ring that is 1" in
diameter and the 10 ring is 2" in diameter. I shot on the full target and just cut out
the centers for the picture.

nly2939.png


Below is a reply to a question about partial full length resizing from "The Rifleman's Journal"

"a full-length sized case in which the neck is also fully sized. There is clearance at the neck and in the body of the case, the closest fit anywhere is the bullet in the throat. If the neck to bullet concentricity is good (although it needn't be perfect), then the bullet will find good alignment in the throat and the case body and neck will have minimal influence. Let's not forget that the base of the case is supported by the bolt face or the extractor to a certain degree as well; this is yet another influence on alignment. As you can see, there are several points from base to bullet that can have an effect. My procedure is to minimize the influence of those that I can control, namely the case body and neck, and let the alignment be dictated by the fit of the bullet in the throat and to some extent by the bolt's support of the base. Barring a seriously out of square case head, I don't think the bolt can have a negative effect on alignment, only a slightly positive effect from minimizing "case droop" in the chamber. Given that a resized case will usually have a maximum of 0.001" diametrical clearance at the web, this isn't much of a factor anyway.

In conclusion, I believe that allowing the bullet to find a relatively stress-free alignment in the throat by full length sizing (including the neck) and turning necks to enhance concentricity gives the bullet the best probability of a well-aligned start into the rifling."

The Rifleman's Journal
Germán A. Salazar

You may also find that a standard Forster non-bushing full length die may reduce the amount of runout. At the Whidden custom die website they tell you they get the most concentric cases with non-bushing full length dies. You are using a body die and then neck sizing with a bushing die in two operations.

NOTE, the U.S. Military conciders match grade ammunition to have .003 or less bullet runout.

Below the Forster full length die produces less neck runout than a Redding bushing die.

 
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Bergers may need a special seating stem as mentioned due the shape of the bullet. In other words the stem might not be contacting the bullet circumference but rather just the tip introducing some wobble.
 
hunter5425 said:
Bergers may need a special seating stem as mentioned due the shape of the bullet. In other words the stem might not be contacting the bullet circumference but rather just the tip introducing some wobble.
Click to expand...

This man has his thinking cap on and this would be the first thing I would check.

I hate it when other people come up with better ideas than I do. :bangHead:
 
bigedp51 said:
This man has his thinking cap on and this would be the first thing I would check.

I hate it when other people come up with better ideas than I do. :bangHead:
Click to expand...

I did take the seating stem out and held it against a bullet to see how it fit - it wasn't exactly a perfect fit, but the nose of the projectile definitely wasn't bottoming out in the stem.

(By "not a perfect fit", I mean that the stem could be tilted left or right on the projectile without much effort - it didn't find a centered equilibrium.)

One thing that I saw in a different forum was using a drop or two of hot-melt glue in the stem to create a "custom" seating stem for that particular bullet, with the advantage being that if the trick didn't help, you could just heat up the stem and remove the glue.

The tricky part here would be, given the lack of self-centering, ensuring that the projectile one used to form the glue while it was hot was, indeed centered in the stem - if you didn't get it exactly centered, you'd be ensuring that any bullets seating with that stem would be off until you re-did it... which would be somewhat tedious, depending on how many times one had to repeat the process to get it right.

I suppose another option could be machining a slight angle into the stem to match the angle that the bullet makes where it contacts the seater.

I should have mentioned that I'm using a .261 bushing, which leaves the necks at about .2595 after sizing. Unfortunately, I don't have a .262 on hand to try for a thou larger. May have to hunt one up - anyone want to trade for a .258 that I'll likely never use? :)

(Necks are annealed each firing as well.)

Seating stem moves smoothly in the sleeve, and the sleeve moves smoothly in the die.

That said, one thing I did notice is that the brass has a bit of wiggle room in the case supporter/sleeve at the bottom - maybe 0.3mm (sorry to mix units... all other measurements have been in inches). Not sure if this is normal with a 6PPC USA seater and a 220 Russian fire-formed case? It's just enough room that you can hear a very faint rattle if you move the case head back/forth in the sleeve.
 
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Wow, that is a tight fit.... try another stem or seater... I prefer Forster seaters.

When you put the stem on a bullet, the circumference of the stem will sit evenly on the bullet nose/ogive. I wouldn't bother with the hot glue for the reasons you have already identified... and hot glue is a soft plastic which will wear with use.

Jerry
 
hunter5425 said:
Bergers may need a special seating stem as mentioned due the shape of the bullet. In other words the stem might not be contacting the bullet circumference but rather just the tip introducing some wobble.
Click to expand...

Agreed... Anyone who is seating any kind of VLD projectile (Berger or otherwise) and Redding Micrometer Seating die is WELL advised to invest the $30 (or so) into Redding VLD seating stem.

TELL TALE SIGN: If you are running a VLD-style bullet and the original seating stem that came with your Redding Competition Seater, then you are probably getting a somewhat deep ring near the top of the bullet after you seat one? … if so, you definitely should get the VLD stem...

I had this issue with Berger 90 VLDs, and the stem replacement cut my runout in half (to a average TIR of about 0.002)… When I was using the original stem (coupled with strictly neck sizing only) I was often getting runout upwards of 0.006 in my 223 Remington.

While I like to support CGN contributing businesses, I don't know which ones carry them. But I know for certain that X reload has ample Redding parts.
 
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Munkey1973 said:
Agreed... Anyone who is seating any kind of VLD projectile (Berger or otherwise) and Redding Micrometer Seating die is WELL advised to invest the $30 (or so) into Redding VLD seating stem.

TELL TALE SIGN: If you are running a VLD-style bullet and the original seating stem that came with your Redding Competition Seater, then you are probably getting a somewhat deep ring near the top of the bullet after you seat one? … if so, you definitely should get the VLD stem...

I had this issue with Berger 90 VLDs, and the stem replacement cut my runout in half (to a average TIR of about 0.002)… When I was using the original stem (coupled with strictly neck sizing only) I was often getting runout upwards of 0.006 in my 223 Remington.

While I like to support CGN contributing businesses, I don't know which ones carry them. But I know for certain that X reload has ample Redding parts.
Click to expand...

I just realized that I've got an unused 6mm VLD seating stem laying around from a "just-in-case" order several years back - these same projectiles seem to sit a bit deeper into it than they do in the one in the seater die currently. Will try it on half the batch when I charge and seat this batch and compare results. Hadn't realized how much longer it was than the normal seating stem... (These projectiles aren't VLD, but I've got nothing to lose by trying it out.)

Thanks again.
 
Follow-up:

Numbers improved somewhat during this cycle over last cycle. I did 40 with pretty much the same setup/process as previous, and 10 with the VLD seater stem.

Average run-out of all loaded bullets measured on the neck was exactly the same as previous cycle at 0.0016; none worse than 0.003.

Average run-out of all loaded bullets measured at the ogive was down from 0.0056 last cycle to 0.0033; there were two at 0.006 and six at 0.005.

Average run-out of the 10 loaded bullets seated with the VLD stem measured at the ogive was a bit lower at 0.0031 - however, with a sample size of 10, probably not enough difference to be statistically significant.

Note: these numbers are for total up-to-down movement, not for deviation from the centerline of the round, so I'm not sure how to categorize these using Big Ed's statement of "NOTE, the U.S. Military considers match grade ammunition to have .003 or less bullet runout.". If the US Army is happy with 0.003 deviation from centerline, then I guess I can be, too... ;)

(However, if their criteria means maximum 0.0015 deviation from centerline, then I guess I've still got work to do...)

Going tools down for the night...
 
way to involved, Tammy loads her ammo with a lee scoop set and seats the bullets by eye with a hammer, she knows something we don't, and her targets don't lie........but my windflags sure do
 
Thought I'd wrap this thread up...

I believe I've figured out why I was getting "interesting" concentricity readings for the 6ppc - I've just realized, to my disgust, that the Redding 6PPC dies that I'd ordered in from Brownells for this rifle are "6PPC USA", which apparently translates to "6PPC Sako".

When I ordered the dies, I knew about the Sako variation, but figured that as the web-page simply listed the set as "6PPC", then they would adhere to the original 6PPC standard (i.e. .263 neck), not the Sako version (.269 or slightly larger depending on where you read the specs). My fault for not asking, I suppose.

To muddy the waters still further, I've also seen references to "6ppc custom" and "6ppc match", both of which sounds like they would be non-original-standard, but (I'm pretty sure) both refer to the .263 size.

Brownells will take them back, postage-paid, but I like the full-length and neck bushing dies in the set, and they're doing their job quite nicely.

Now to either decide to live with the current seater/runout, or splurge/wait and get the Wilson arbor 6ppc seater die (which is the only one I've found since re-looking into seaters that I'm relatively positive will match my chamber).

Thanks again for all the responses and suggestions above!
 
I didn't read the whole thread and I've never loaded super accurate ammo. But a podcast with a PRS shooter recently advocated using Mandrel type mouth expander dies to reduce bullet runout. For instance this one.
https://www.sinclairintl.com/reloading-equipment/case-preparation/neck-turning/turning-expander-mandrels/generation-ii-expander-dies-prod38807.aspx
This is the podcast:
https://www.podbean.com/site/EpisodeDownload/PBD7D4C4GTSXS
 
Just a little hint, check neck runout on your resized cases and again after loading and seating the bullet.

A bushing die can induce neck runout the more the neck diameter is reduced during sizing.

A neck size only die does not support the case body like a full length die and this can increase neck runout.

You could try using a Lee collet die instead of the Redding neck sizing bushing die and see if you get less neck runout

At the Whidden custom die website they tell you they get more concentric cases with non-bushing full length dies.

Below the 6.5 Guys get less neck runout with Forster full length dies than bushing dies. The reason for this is a full length die supports and aligns the case body and neck in perfect alignment during sizing. And a bushing die allows the bushing to float and it can move from side to side and even tilt. Bushing dies work best with tight neck chambers with neck turned brass.

 
Op it might be any one of the above giving you your run-out...or it could be something as simple as where your die is sitting in your press. Not many reloaders know this as 99.99 % of us don't require an absolute run-out free product in our reloading. The fact is, that treads are cut to interface easily on both a press and our dies, they have a certain amount of 'wobble" to them until the locking ring is applied. I have indicated a test dial on die bodies and found at least as much run-out as you are finding just from taking a reading, then loosening the locking ring, moving the die 1/4 turn and re-locking it...the thing is that the curve & thread lead of the two mating surfaces contact each other at a different angle. it wont be much at the actual thread site but it magnifies in size at the end of the die barrel. Same thin happens with your seating plug, it is canted ever so slightly when you set the locking ring but combined with the die cant, you can easily end up with the run-out you describe.

You may be able to alleviate the issue...sort of "find the sweet spot" in essence...by testing your die line-up after tightening the locking ring at 1/8 turns of the die and repeating until you find to "0" spot.
 
I square up my dies with a dime...
Not a nickle , penny or a quarter... measure for your self..
dimeS have a very even thickness .
Anyhow..
Figure out where you want to set your die... as far as setting crimp" if it's a hunting cartridge.

Set your ram all the way up, squaring your die to the face of the shell holder make contact with light , minimum pressure .

You want most off the threads for holding the dies "strait," to be pressured up on the locking ring.. not threads inside inside the collet..or the dies body..
IE the surface of your press should be square and plumb with the stoke of the ram. ... the threads and pitch of the threads could never align perfectly... tighten up the ring , then your tension screw...
To remove, and Install
USE a wrench to hold the collet " the large sleeve insde your press, IF yours has one" ..
another wrench to crack your die out of the press.
And your golden..
Same goes with neck dies,,, full lenght resizing dies,,, JUST PULL THE DEPAPING ROD OUT FIRST..
tight is right when your trying to take run out if equation.. good LUCK with your quest O.P.
FYI.. reloading is not shooting , if you can call wind, YOU WIN
DAME WIND..lol have fun , stay safe CGN'S
Hope this helps
 
ShootingNewbie said:
Thought I'd wrap this thread up...

I believe I've figured out why I was getting "interesting" concentricity readings for the 6ppc - I've just realized, to my disgust, that the Redding 6PPC dies that I'd ordered in from Brownells for this rifle are "6PPC USA", which apparently translates to "6PPC Sako".

When I ordered the dies, I knew about the Sako variation, but figured that as the web-page simply listed the set as "6PPC", then they would adhere to the original 6PPC standard (i.e. .263 neck), not the Sako version (.269 or slightly larger depending on where you read the specs). My fault for not asking, I suppose.

To muddy the waters still further, I've also seen references to "6ppc custom" and "6ppc match", both of which sounds like they would be non-original-standard, but (I'm pretty sure) both refer to the .263 size.

Brownells will take them back, postage-paid, but I like the full-length and neck bushing dies in the set, and they're doing their job quite nicely.

Now to either decide to live with the current seater/runout, or splurge/wait and get the Wilson arbor 6ppc seater die (which is the only one I've found since re-looking into seaters that I'm relatively positive will match my chamber).

Thanks again for all the responses and suggestions above!
Click to expand...

Best of luck receiving your new dies from Brownells. I placed an order with Brownells over three weeks ago. After tracking it with USPS it went as far as Canada Customs, it's MIA. I was going to suggest to check-out your size die, in particular the stem, to assure that it is centered inside or hasn't bent. Glad that you figured out your issue.
 
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