Where did the runout come from?

[dstoenner]

A brief history before we get into this. I have been shooting the 6BR for maybe 10 years now. It has been consistently the most accurate gun/caliber I own. My original load sequence was to size the cases with a Whidden FL bushing sizer. A the time I was using a .266 Redding bushing. I then loaded and seated my bullets with a Redding Competition Seater. In general that gave me loaded runout of about 30% .001 runout, 40% .002 runout and the rest usually .003 with a .004 or so. I originally bought 3 boxes of Lapua brass. I kept each box as its own group. I weight sorted the brass and had about 90+ in each box. I would load an entire box of brass all at once but usually split it between 2 bullets. Life was good (till it wasn't).

I shot one barrel out so I bought a new one. That used 9 reloadings of my Lapua brass. While I was waiting for the second barrel I decided I would get the brass annealed. When I got it back it all needed to be sized but my necks were getting thinner so I went to my .265 bushing. Sized them all and then went to reload batch #1 like I had done. Low and behold the runout was terrible. After a lot of detective work I figured out the .265 bushing was out of round. But in the process I found an even better solution that had been suggested in one of the articles on Accurate Shooter. That was to get a honed Forster die. WOW what a difference. With the Whidden set up with a Whidden bushing, I would get 80% 1's with the rest 2's and 3's. With the Forster they were coming out 100% 1's. I needed to work through these 300 cases with bad runout and then resize them with the Forster. That all happened at the beginning of this month.

So I needed to get some more ammo so I pulled out set #1 (fired 10X) divided it up at random between two trays. I was going to load the 105 Berger Hybrid in one group and the Berger 68 Target. HPFB, in the other group. I choose the 105 first and loaded it up. My runout totals were just like I had before the fiasco of the bushing took place.

.001 Runout - 27
.002 Runout - 17
.003 Runout - 0
.004 Runout - 1

So all looked good. I then loaded up the 68's and got this runout distribution:

.001 Runout - 14
.002 Runout - 15
.003 Runout - 5
.004 Runout - 12

I say WHAT?? 12 .004 runout was back to the original bad stuff, yet these were from a random distribution. Where did this come from?

Something else was going on. I thought about it for a day. I have a Wilson micrometer top in-line seater. I didn't want to experiment with my good batches but I had some 1X fired I bought off of GunBroker that were already sized. So I sorted out 10 .001 runout as an experiment and loaded 10 up with the Wilson.

Here is a picture comparing 3 different experiments I did. The loading block on the top is the Wilson in-line seater. Each vertical column is .001 increase of runout starting with .001.

As you can see it sort of mirrors exactly the Redding results but worse in percentages. I then thought I had better be sure so I selected another 10 and loaded them up with the Redding just to compare apples and apples.

That is the second loading block in the picture. it actually was better than the Wilson but more like what I saw with my 10X fired cases from batch #1.

I then took the remaing 43 cases and sized them with my Forster die. All of them came out .001 or less runout. I selected at random 10 more and loaded them up with my Redding Competition Seater and those results are the bottom loading block.

Better but not the 105 results.

I am still scratching my head a little. It maybe a while for me before I get back to the range to test the 105 vs 68 load for accuracy. Thought I would share with everybody to see if anybody else has bumped into this sort of thing. Unfortunately I don't keep runout distribution results on my 6BR so I can't go back and see what the 68 used to load at. The Berger 68 has never been the best bullet for me. The 90 Berger Target is the best for accuracy of any bullet I have shot in the 6BR, even better than the 105, although it is second for me.

Sorry for the long report but without the background it is hard know where i came from and why I was going the way I was going. Anybody else had issues with the Berger 68 Target? I tried Bart's Ultra's and they weren't any better.

David

 

[gunsandgunsmithing]

Most runout issues can be traced to the sizing operation, fwiw.

 

[mikecr]

Check thickness variance of offending cases with a good ball mic.

 

[Murray Brook]

Agree with @gunsandgunsmithing . Did you check all your cases for run-out after the sizing, before seating the bullets. If the run-out is good for the case necks then the culpurit would be the seating operation/and or die. JMO

 

[PopCharlie]

Im in agreement with gunsandgunsmithing. In my experience, runout comes from the sizing die. The bushing dies are the worst for causing runout, IMO. I use Forster bencrest non-bushing FL sizing dies. Runout on my sized cases is .0000 +- .0005. Seating us another story. I seat using Wilson dies and an arbor press. This set up produces .002 runout or less. Occasionally i will get one that is at .003 to .0035, but never any more than that.
Having said all this, alot of better shooters than me say runout makes no difference on target.

PopCharlie

 

[GlennK]

Can anyone show that the runout shows on paper? I understand uniformity is ideal, but it seems to not show for me. For example if you took 5 with perfect runout and 5 with say 4 or more thousandths run out, colored them up and then shot them blindly on paper; would you be able to tell a difference?

 

[gunsandgunsmithing]

Can anyone show that the runout shows on paper? I understand uniformity is ideal, but it seems to not show for me. For example if you took 5 with perfect runout and 5 with say 4 or more thousandths run out, colored them up and then shot them blindly on paper; would you be able to tell a difference?

Tests have been published but I'm more with you. Maybe it has to do with whether you jump or jam your bullets. I tend to run some amount of jam and I see little or no difference.

 

[dstoenner]

Agree with @gunsandgunsmithing . Did you check all your cases for run-out after the sizing, before seating the bullets. If the run-out is good for the case necks then the culpurit would be the seating operation/and or die. JMO

I did check these because it was the first time i was using the forster sizing die so i wanted to make sure it was doing the job.

I didn’t say this in my intro but all cases were neck turned to start with before being shot the first time.

in my limited testing the wilson was not as good as the Redding seater for the 68s. The point i was making was that the same cases seated with the same seater produced drastically different seating results based on bullet. Both seaters have VLD stems in them.

at 100 yards i agree that the runout may not make any observable difference. For me it is a QC check of my whole process. This was a big bump in the road for me.
David

 

[mikecr]

Did you check thickness variance of cases before neck turning?

 

[Straightshooter1]

Can anyone show that the runout shows on paper? I understand uniformity is ideal, but it seems to not show for me. For example if you took 5 with perfect runout and 5 with say 4 or more thousandths run out, colored them up and then shot them blindly on paper; would you be able to tell a difference?

I've done this and it definitely showed a difference (though a small one) . . . even at 100 yds. But whether or not you can see the difference will depend a lot on the precision of the load and other prep work. The smaller the group that can be made, the easier it is to see a small difference.

 

[dstoenner]

Did you check thickness variance of cases before neck turning?

Yes and they varied about .001 so i cleaned them up leaving as much neck thickness as possible

 

[milliron]

I have had the same problems as you. The only way to find what causes the problem , is to inspect your cases at each stage of loading. I spent several hours checking run out at each stage of loading and found out that there are several small operations that have some collective impact on the loaded round.
1 make sure that the cases are not to long, with the Wilson seater if the case is too long the case head will extend below the bottom of the die and not sit square when seating the bullet.
2 case mouth should be as square to the case as possible, make sure there is no burr after trimming. When you chamfer the case mouth, do this carefully, you don t need much to start the bullet. try to make it the same all around the case mouth
3 use Redding shell holders, I find them a cut above the others. I use mandrels to size my cases mouths, if you are loading 6 br I would use one that is sized at .243, this will give about .001 bullet grip. in addtion the mandrel will let you segregate your cases by tension and allow you to separate them from the others.
4 brush case mouths, this helps, use a nylon brush. I lubricate with dry moly.
I hope this will help you, I think that what i do does reduce flyers, but I can not prove it. Henry

 

[Uncle Ed]

I have had the same problems as you. The only way to find what causes the problem , is to inspect your cases at each stage of loading.

I agree, I check the neck runout after sizing and again after seating the bullet. This lets you know where the problem starts.

 

[Alex Wheeler]

If you have not done it in a while, trimming and chamfering can help. As brass grows it can sometime get out of square at the end of the neck and that creates runout as you seat the bullet.

 

[Fuj]

If you have not done it in a while, trimming and chamfering can help. As brass grows it can sometime get out of square at the end of the neck and that creates runout as you seat the bullet.

What Alex said. I will also note that uneven annealing can be a
culprit. Bullet may go in straight, but coming out of the die can
spring it to one side ever so slightly.

 

[dstoenner]

I have had the same problems as you. The only way to find what causes the problem , is to inspect your cases at each stage of loading. I spent several hours checking run out at each stage of loading and found out that there are several small operations that have some collective impact on the loaded round.
1 make sure that the cases are not to long, with the Wilson seater if the case is too long the case head will extend below the bottom of the die and not sit square when seating the bullet.
2 case mouth should be as square to the case as possible, make sure there is no burr after trimming. When you chamfer the case mouth, do this carefully, you don t need much to start the bullet. try to make it the same all around the case mouth
3 use Redding shell holders, I find them a cut above the others. I use mandrels to size my cases mouths, if you are loading 6 br I would use one that is sized at .243, this will give about .001 bullet grip. in addtion the mandrel will let you segregate your cases by tension and allow you to separate them from the others.
4 brush case mouths, this helps, use a nylon brush. I lubricate with dry moly.
I hope this will help you, I think that what i do does reduce flyers, but I can not prove it. Henry

1) I trim my cases every time they are fired. I am sort of anal that way.
2) I inside and outside chamfer the mouth every time after triming.
3) I agree that Redding makes great shell holders and that is what I use for all of my operations in the press.

This is what is so frustrating to me. I have worked out a system that gives me great cases and loaded runout that is excellent. The 105's showed that but then along came the 68's and they won't line up (no pun intended) within the same group of prepped cases that the 105's did awesome. In fact they didn't do it in another group of cases only fired 2X.

David

 

[dstoenner]

If you have not done it in a while, trimming and chamfering can help. As brass grows it can sometime get out of square at the end of the neck and that creates runout as you seat the bullet.

I do it every time. Trim then chamfer. Just a part of my process. I believe that you should always load with a case that is as much like the last time they were loaded so that once you get a good load you can repeat it without variables. But...

 

[dstoenner]

What Alex said. I will also note that uneven annealing can be a
culprit. Bullet may go in straight, but coming out of the die can
spring it to one side ever so slightly.

I check my loaded concentricity on the bullet close to the ogive. I will go back this afternoon and remeasure my loaded 68's at the neck and report back.

One person said I should brush the necks with a dry lubricant before loading. I will try that also and report back. That is one thing I have never done in the 18 years I have reloaded. Never needed to.

David

 

[LCazador]

I did check these because it was the first time i was using the forster sizing die so i wanted to make sure it was doing the job.

I didn’t say this in my intro but all cases were neck turned to start with before being shot the first time.

in my limited testing the wilson was not as good as the Redding seater for the 68s. The point i was making was that the same cases seated with the same seater produced drastically different seating results based on bullet. Both seaters have VLD stems in them.

at 100 yards i agree that the runout may not make any observable difference. For me it is a QC check of my whole process. This was a big bump in the road for me.
David

The big question is: where is each bullet seated in relation to the lands? Back in the day more jam resulted in better groups especially with brass that had been fired 8-10 times. I scrap brass after 9 or ten cycles. It just doesn't shoot. And annealing seems to make things worst so trying to save those cases after 10 shots by annealing isn't the answer. While most concentricity problems happen with the sizing die, it's important to know that a misalignment problem with the ram in your press can cause such problems. This is why the tap in dies were used in the early days of benchrest. One other thing to consider is the accumulation of carbon in the necks. It does not accumulate uniformly around the inside of the neck so seating against the deposits disturbs uniformity. I suspect this more than any misalignment problems. This creates problems with bullet tension as well. My opinion of course.

 

[rogina]

I check my loaded concentricity on the bullet close to the ogive. I will go back this afternoon and remeasure my loaded 68's at the neck and report back.

One person said I should brush the necks with a dry lubricant before loading. I will try that also and report back. That is one thing I have never done in the 18 years I have reloaded. Never needed to.

David

Remember, the 68 grain bullets have an expandtion ring if they are not a boattail.