Run-out help needed

[Bullet bumper]

A bushing / body die like a Redding S die is in my opinion , a "full lenght sizing capable die "
With the bushing adjusted down to the shoulder junction it will size the same places as a conventional FL die. However if the bushing is adjusted to partial neck size then it is not a Full length die by classical definition.
So it is unhelpful to argue about what it is called . It is better to focus on what it can do and identify it by it's production name .
For a bolt gun I prefer the two separate sizing dies neck and body but an S would work fine also with correct adjustment . For the Auto , lever or slide action the S die is very convenient . Speeding up the process , because you want easy chambering ammo every time and when reloading time is short . Also some like to have the exact same case fit each time as they feel it enhances accuracy.
Resizing the body after 5 or 6 reloads means varying case fit from first reload to reload 6 . I have never found this a big accuracy issue but in a BR gun it may show up more .

 

[Bart B]

Bulletbumper, I agree with what you say about full bushing dies.

But I don't think Mikecr would never consider, even if he saw it in print on benchrest web sites, that those stool shooters use full bushing dies to size the whole fired case body and neck down and set the shoulder back a bit these days to get best accuracy:

Custom Dies Work Best
Most top 6PPC competitors run their ammo at pretty high pressures. Such pressures demand that cases be full-length sized each time they are loaded. But the trick is sizing the case just enough to allow proper feeding/extraction and no more. To achieve this perfect fit, nearly all the "top guns" use custom dies, precisely fitted to the dimensions of fired brass. Typically, a custom sizing die will reduce the case diameter at the shoulder .00075" to .001". The die will also allow for a little bit of shoulder bump. Nearly all the top shooters use bushings for neck-sizing. Having a variety of bushing allows you to compensate for brass that becomes work-hardened. You can also use bushings to tune loads for different bullets or conditions (tighter "grip" tends to increase pressure). For his .263"-necked brass, Speedy Gonzalez has a full set of carbide neck bushings, in .0005" increments from .256" to .261". He also has four different body-sizing dies, which allow him to choose the exact amount of sizing he wants, both at the shoulder and at the web.

I've used full length sizing dies with different case body section and neck diameters for decades and never had any accuracy or case life problems. I've known such sizing tools have been producing best accuracy that way for decades. The most accurate 30 caliber bullets shot I know of came out of cases so sized.

Besides, rimless bottleneck cases center up front in the chamber perfectly regardless of how much clearance there is between the case right behind the shoulder and that point in the chamber. Even a .243 Winchester round with zero bullet runout centers up front very well in a .308 Win. chamber if fired, even with .010" clearance around that same point between case and chamber.

 

[Bullet bumper]

I am pretty much with you on all that. One thing we should note is most BR loadings that are using bushings are also neck turning the cases .
The bushing does not work all that well on unturned factory brass that may be variable in dimentions. If the brass is good then it's fine . However the Lee collet die will work on unturned brass and neck turned .
We must not mix up what is suitable to competition and what suits the average home loader for hunting and casual target shooting.
How well a case centers is also a function of how neatly it fits . If a case is over sized it will lay in the bottom of the chamber as new unfired factory ammo does in factory chambers .
If the neck is a neat fit like a fitted neck turned case then it can't lay in the bottom of the chamber if the case neck is always a neat fit.
So even if the base is reduced in diameter and a slight shoulder bump used the tight neck does most of the work keeping the bullet in the center of teh bore.
That is why I use partial neck sizing in every bolt gun . I leave a short second shoulder that is never sized to do most of the centering work at the front and minimum body sizing at the rear and shoulder .

 

[Bart B]

How well a case centers is also a function of how neatly it fits . If a case is over sized it will lay in the bottom of the chamber as new unfired factory ammo does in factory chambers.

While this premise is often stated as fact, it is a myth. However, when the round's pushed into the chamber and the bolt's till open, then yes, it will lay in the bottom of the chamber regardless if it's a new, fired or resized in any way. Here's why.

When the bolt's closed on a rimless bottleneck case and it has an in-line spring-loaded ejector pushing on the case head, there's enough force in the ejector spring to push the case forward until it stops against the chamber shoulder. As the case shoulder's the same angle as the chamber shoulder, it will very well perfectly center at that place. There's clearance all around the case to the chamber except at the back end at its pressure ring. That is where the case is typically pressed against the chamber wall by the extractor.

When the firing pin drives hard into the loaded round's primer, that further drives the case hard into the chamber shoulder oft times setting the case shoulder back a thousandths or more from the pin's impact. If the case wasn't pushed forward by an in-line ejector but was in an action with an external claw type ejector, it sure is by the force of the firing pin.

Non-believers of this should cut the chamber end off a worn out barrel, face it off square to the chamber axis right at the chamber mouth point, screw it into a receiver, then chamber some new or sized empty cases in it. Use a loupe with a scale in thousandths in it to measure the clearance around the case mouth to the chamber neck. Do this with a .308 Win. chamber section then load a .243 Win. case into it and see how perfectly centered its neck is in that way oversize chamber neck.

If new cases really did lay in the bottom of oversize chambers when fired, then how in the dickens did M1 and M14 match rifles (strong-springed in-line ejectors) with their big, MIL SPEC chambers shoot minimum size cases in commercial match ammo into no worse than 4 inches at 600 yards? Even very accurate Palma rifles with SAAMI spec, loose-neck chambers shoot brand new ammo into 1/2 MOA at 600 yards.

Does a rimless bottleneck GO headspace gauge rest in the bottom of the chamber and have clearance at its shoulder when the bolt closes on it and there's a bit of binding up felt? Where does its coned/tapered front end go when this happens?

 

[Mikecr]

Bart, your case centering because of an ejector plunger and re-headspacing on firing is a myth, because it's declared unqualified.
A 6br or a 6xc doesn't do this, where a 243win might, because the shoulder angles are different.
And there is the assumption of an ejector plunger, but standing blade, or no eject actions are common. This because some shooters do not want an ejector pushing cases out of centerline.

My 6.5wssm action(BAT) utilizes standing blade ejection. The cases do not change in HS on primer firing. And they are held centered by correct sizing -with well under 1thou of TIR off ogives.
This is a fitted chamber and the ONLY sizing needed, ever, is shoulder bumps(35deg, 1thou). With this, my bolt turns are smooth as cream.
I have over 30 reloads on these cases, and their measured H20 capacity still matches logged at 3rd fireforming.
I use a JLC body die for bumping, and I use a custom Wilson bushing die to slightly increase tension with -1/2thou & .125" length of sizing(cuz that's what my load liked). I also use only Wilson's for seating. I get the .125" length of sizing with a machine bushing, similar to a washer shim mentioned earlier.
Now this is just one cartridge, an example for diversity in this discussion. I know that different cartridge designs result in different reloading plans, and that overall generalizations are usually wrong. All cartridge designs are not equal.

Do 'FL bushing dies' size the entire neck?
If so, I did not know this, and would concede that such a die would function as a FL die.
I don't have any issues/dislikes at all with body-bushing dies. JLC Precision has made several for me.
But I prefer separate body and bushing neck sizing myself. So I don't use JLC's dies with bushings. I leave that part to my Wilson inlines(removing the press).

Where reloaders could get messed up is in talking about partial neck sizing with FL dies. Obvious to many of us is that partial neck sizing is different with a FL bushing die, than an actual FL die.
This is why I don't like the TERM 'FL bushing die'. I call it a body-bushing die.
Tryin to help here

 

[Bart B]

Bart, your case centering because of an ejector plunger and re-headspacing on firing is a myth, because it's declared unqualified.

Who declared that case centering thing unqualified? Someone unqualified to do so, in my opinion. Here's why.

I've taken the firing pin, extractors and ejectors out of the bolts/actions on .222 Rem,. .22-250 (case the 6XC is based on but shorter than), .243 Win., .270 Win. 7x57 Mauser. .300 Savage, .308 Win., .30-06, 8x57 Mauser and other primed cases to see what happens when they're chambered in rifles with the barrel pointing straight up. There's no external forces anywhere on the case except gravity. Coating the case shoulders with machinist's dye, letting it dry then chambering those cases with a few thousandths of head clearance, then opening the bolt to inspect them, none had any touch marks on their shoulders; they had clearance at the shoulder when chambered. Chambering those cases then pushing them forward with the firing pin until they stopped against the chamber shoulder, they all had contact marks all the way around. If they didn't center perfectly in the chamber shoulder, they wouldn't have contact marks all the way around.

I therefore declare your "ejector plunger and re-headspacing on firing is a myth, because it's declared unqualified" comment one based on ignorance. Be careful on how you respond to this.

A 6br or a 6xc doesn't do this, where a 243win might, because the shoulder angles are different.
And there is the assumption of an ejector plunger, but standing blade, or no eject actions are common. This because some shooters do not want an ejector pushing cases out of centerline.

Extractors often push case heads off center against the chamber wall at the pressure ring point on the case; the back end of such cases are always off center in the chamber. And in line ejectors force axis is parallel with the chamber axis so whatever off center thing they do with loaded rouns ain't very much.

Do 'FL bushing dies' size the entire neck? If so, I did not know this, and would concede that such a die would function as a FL die.

Again, another premis based on ignorance. Glad to see you admitted your error in reasoning. I've done that myself a few times, then jumped into the world or reality with real things and got informed.

It's OK to be ignorant about something then get cured by being better informed about it. Just stay far, far away from dumb and stupid; these two are nye impossible to cure.

 

[paphil]

First of all. this has gotten way too high tech for a beginner! All good stuff but it will discourage some guys who are just starting. I like the idea of a sharpie mark on the case and then see if the run out is always the same side or direction. Also, I've marked the cases after loading and placed them in the gun with the runout always in the same position and this improved group sizes. The one thing that I did that seemed to help runout the most was loosening the nut that holds the seater cone and just setting it barely finger tight. It seems that this lets the cone float and allows the bullet to center a little better. Also agree that the cone must rest on the ogive and not on the tip. Take it apart and look at it to tell! I do the same when neck sizing, the small nut that holds the deprimer /sizing pin is loosely finger tight to allow it to float to the center when the shell is pulled out over it to resize the neck. You have to keep checking to assure they don't come loose and cause changes in the seating depth but this brought my runout from ,007 on average down to .003 or less. Good compitition dies are worth the cost if you are wanting an easy fix, mine usually give less than .002 runout.
Last thing I would reccomend is to stay away from cheap brass because it usually will have some hidden flaw , thin and uneaven thickness or rim or belt problems. with the demand for good brass, price is an early warning! Good Luck loading!

 

[Bart B]

Also, I've marked the cases after loading and placed them in the gun with the runout always in the same position and this improved group sizes.

That's been happening for decades. And it does help indeed.

Service members on military teams would sometimes spin issued match ammo, mark the runout high point on the case head, then put the round back in the 20-round cardboard box. Then load those for single round matches; mark at the top of the chamber. Officials running the match sometimes would catch that and declare the ammo as illegal 'cause the rules state the ammo has to be unmodified as issued; that black mark was considered a modification. So folk would just spin the ammo then put it back in the box with the rounded indexed with the high runout point towards the front of the box. Accuracy at the longer ranges got better by 1/2 MOA or more.

 

[Bullet bumper]

While this premise is often stated as fact, it is a myth. However, when the round's pushed into the chamber and the bolt's till open, then yes, it will lay in the bottom of the chamber regardless if it's a new, fired or resized in any way. Here's why.

When the bolt's closed on a rimless bottleneck case and it has an in-line spring-loaded ejector pushing on the case head, there's enough force in the ejector spring to push the case forward until it stops against the chamber shoulder. As the case shoulder's the same angle as the chamber shoulder, it will very well perfectly center at that place. There's clearance all around the case to the chamber except at the back end at its pressure ring. That is where the case is typically pressed against the chamber wall by the extractor.

When the firing pin drives hard into the loaded round's primer, that further drives the case hard into the chamber shoulder oft times setting the case shoulder back a thousandths or more from the pin's impact. If the case wasn't pushed forward by an in-line ejector but was in an action with an external claw type ejector, it sure is by the force of the firing pin.

Non-believers of this should cut the chamber end off a worn out barrel, face it off square to the chamber axis right at the chamber mouth point, screw it into a receiver, then chamber some new or sized empty cases in it. Use a loupe with a scale in thousandths in it to measure the clearance around the case mouth to the chamber neck. Do this with a .308 Win. chamber section then load a .243 Win. case into it and see how perfectly centered its neck is in that way oversize chamber neck.

If new cases really did lay in the bottom of oversize chambers when fired, then how in the dickens did M1 and M14 match rifles (strong-springed in-line ejectors) with their big, MIL SPEC chambers shoot minimum size cases in commercial match ammo into no worse than 4 inches at 600 yards? Even very accurate Palma rifles with SAAMI spec, loose-neck chambers shoot brand new ammo into 1/2 MOA at 600 yards.

Does a rimless bottleneck GO headspace gauge rest in the bottom of the chamber and have clearance at its shoulder when the bolt closes on it and there's a bit of binding up felt? Where does its coned/tapered front end go when this happens?

No it is not a myth mate in all cases , just look at the bulge on one side of a fired case coming out of most factory chambers . It is usually on the top side unless extractor or a plunger ejector pressure pushes it some place else . Eitherway the case is fire formed not concentric to the chamber .

 

[Bart B]

No it is not a myth mate in all cases , just look at the bulge on one side of a fired case coming out of most factory chambers . It is usually on the top side unless extractor or a plunger ejector pressure pushes it some place else . Eitherway the case is fire formed not concentric to the chamber .

I was first told this back in the 1960's. So I marked a bunch of .308 Win. cases, indexed that mark at 12 o'clock in the chamber (hoping they would not twist too much to the right when the bolt closed on them) then fired them; some in factory chambers, others in MIL-SPEC chambers.

The cases had that bulge at different points around the case from the mark. So, I cut the heads off the cases and measured the case wall thickness all the way around. The thinnest part of the case body was always at the same point as that mark. Those with the most uniform case wall thickness had the least amount of single-point bulge part.

As case body thickness ain't uniform all the way around, that's why they're more oval shaped after firing. Chambers are oval, too, but to a much, much smaller amount. No such thing as either being perfectly round.

I don't understand why a fired case would expand the most where it's pressed against the chamber wall; top, side or bottom. And virtually all of an in-line ejector's force axis is parallel to the chamber axis (ain't that why it's called "in-line?"), so it'll just push the case forward until it stops at its headspacing point.

 

[idefendem]

The answer to run out is simple and, judging by the postings, somewhat overlooked. You can take 2 paths: one, is a lot of fooling with dies and adjustments; two is simple: buy a concentricity guage from Hornady and you can correct your bullet run in hand loaded or in factory loaded ammo to zero, or thereabouts. They are about 80 bucks and are pleasure to use. You can hold to a run out standard of .005 or less with minimal effort regardless of seating dies used. Give it a try.

 

[Bullet bumper]

I was first told this back in the 1960's. So I marked a bunch of .308 Win. cases, indexed that mark at 12 o'clock in the chamber (hoping they would not twist too much to the right when the bolt closed on them) then fired them; some in factory chambers, others in MIL-SPEC chambers.

The cases had that bulge at different points around the case from the mark. So, I cut the heads off the cases and measured the case wall thickness all the way around. The thinnest part of the case body was always at the same point as that mark. Those with the most uniform case wall thickness had the least amount of single-point bulge part.

As case body thickness ain't uniform all the way around, that's why they're more oval shaped after firing. Chambers are oval, too, but to a much, much smaller amount. No such thing as either being perfectly round.

I don't understand why a fired case would expand the most where it's pressed against the chamber wall; top, side or bottom. And virtually all of an in-line ejector's force axis is parallel to the chamber axis (ain't that why it's called "in-line?"), so it'll just push the case forward until it stops at its headspacing point.

It expands the most where it's " not " pressed against the chamber wall .

 

[Mike027]

I almost purchased the Hornady gauge. There have been some good reviews on it. I thought it might be best to try and correct the problem from the start. I have a lot to think about. I appreciate everyone's discussion and recommendations. Mike

 

[Bart B]

It expands the most where it's " not " pressed against the chamber wall .

I don't see how that can happen. The pressure inside the case is way, way higher than the pressure it has against the chamber as pressed there by the extractor.

Every case wall thickness I've measured is thinnest where the pressure ring swell is the greatest.

And some cases have the same pressure ring swell all the way around. Does that mean they were floating dead center in the chamber at that point and not pressed against the chamber wall by anything?