Bullet runout/Concentricity

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Jcann

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I’ve handloaded for many years now and at one time I religiously checked bullet runout. For those that are unsure of what bullet runout is I’ll try to explain. One thing we as shooters should desire in a rifle is everything concentric. That is from the bolt face to the muzzle/crown we want everything on the same axis. A quality gunsmith can do this and I’m sure many manufacturers can as well. But the fly in the ointment happens at the handloading table. Hence, this is why I stopped checking bullet runout. No matter what I tried I could not keep the bullet concentric to the centerline of the case. It was always off by a few thousands and sometimes as high as four-thousands. So I stopped checking it, figuring it might show up as a flyer or maybe not at all.

Today, I loaded 50 .260 Rem using new Peterson Brass. I did the normal case prep; resizing, trimming, chamfering, etc. After I finished loading the 50 rounds I thought what the heck, let’s check runout. To my amazement, when I checked it, it was less than one thousandths of an inch for every round. I’m not saying I did anything special because I didn’t, I think it speaks to the quality of Peterson Brass. Now the next check will be at the range.

https://bulletin.accurateshooter.com/2019/02/bullet-concentricity-basics-what-you-need-to-know/
 

KurtM

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Best brass I ever had/have in 308 for run out is Lake City National Match cases. Average run out loading on a Dillon 650 is . 002. This brass was all fired out of M-40 bolt guns and I still have a couple dry wall buckets full.
 

swampratt

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Here is something I have thought about on the runout.
Your brass is New and should be darn near spot on.
Shoot that brass and eject it and reload it a couple times more and check runout.

Doesn't the tool to check runout hold the case head flush or go into the extractor groove?
I think pulling on the rim for extraction could cause bullet runout to be in the higher than .001" range.

Curious if that is something or not.
I have never done anymore than roll a case on the flat formica counter top and look for wobble.

I will stay tuned and see how this plays out.
Interesting for sure.
 

dennishoddy

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Best brass I ever had/have in 308 for run out is Lake City National Match cases. Average run out loading on a Dillon 650 is . 002. This brass was all fired out of M-40 bolt guns and I still have a couple dry wall buckets full.
I have a "few" of the Lake City Match brass in 30-06, some of which has been necked down to .270.
 

Jack Shootza 50

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I’ve handloaded for many years now and at one time I religiously checked bullet runout. For those that are unsure of what bullet runout is I’ll try to explain. One thing we as shooters should desire in a rifle is everything concentric. That is from the bolt face to the muzzle/crown we want everything on the same axis. A quality gunsmith can do this and I’m sure many manufacturers can as well. But the fly in the ointment happens at the handloading table. Hence, this is why I stopped checking bullet runout. No matter what I tried I could not keep the bullet concentric to the centerline of the case. It was always off by a few thousands and sometimes as high as four-thousands. So I stopped checking it, figuring it might show up as a flyer or maybe not at all.

Today, I loaded 50 .260 Rem using new Peterson Brass. I did the normal case prep; resizing, trimming, chamfering, etc. After I finished loading the 50 rounds I thought what the heck, let’s check runout. To my amazement, when I checked it, it was less than one thousandths of an inch for every round. I’m not saying I did anything special because I didn’t, I think it speaks to the quality of Peterson Brass. Now the next check will be at the range.

https://bulletin.accurateshooter.com/2019/02/bullet-concentricity-basics-what-you-need-to-know/
Best brass I've ever used, it's worth the price.
 

Calamity Jake

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I to check runout(not concentricity) of the bullet to the case,
This is all that can be checked because there is no way to establish the true centerline of the case.
All of these runout gages that we use relies on the outside case diameter not the case centerline.
There no tools made that can establish centerline because of the design of the case.
Any out of roundness in the case body affects runout.
Even if the cases were made on a lathe there would be on way to establish true centerline.
 

Jack Shootza 50

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I to check runout(not concentricity) of the bullet to the case,
This is all that can be checked because there is no way to establish the true centerline of the case.
All of these runout gages that we use relies on the outside case diameter not the case centerline.
There no tools made that can establish centerline because of the design of the case.
Any out of roundness in the case body affects runout.
Even if the cases were made on a lathe there would be on way to establish true centerline.
And that is why Bench Resters turn all their necks to get them running as true as possible.
 

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