Bullet Concentricity/Runout

[cjc5062]

Hi all, I upgraded my whole reloading setup recently and just got everything set up. Using an Amp Annealer, Amp Arbor Press, Short Action Customs Infinity in-line Seating Die, Area 419 Zero Gen II press (for sizing), Area 419 M series FL sizing dies, Accuracy One Concentricity gauge, and Henderson Trimmer.

I'm trying to squeeze every little bit of accuracy out of my rounds. I know all this isn't necessary, but it's my hobby and I enjoy trying to chase every minuscule imperfection.

I recently loaded up some new cases (Peterson) and am not thrilled with the bullet Concentricity. I got anything from 0.001" to 0.004" on my bullet Concentricity. I anneal, full length size, trim and then seat using the arbor press and in-line seating die. For 6.5PRC I'm using the standard SAC neck guide with the M2 seating sleeve as recommended from SAC.

I believe my process is pretty dialed in, but the only thing I can think about is whether the fact I'm compressing powder for these rounds is making me get slight variations in runout? I've also measured my neck Concentricity and am getting .0005" runout on the neck, which should be great.

Appreciate any help!

 

[Steve Donlon]

Are you shooting any better with all the upgraded stuff? I have always upgraded one thing at a time to see what I need and what is good enough for me. There are so many variables to becoming a really good shot. But it looks like you are off to a good start.

 

[Dave M.]

Don’t get hung up on concentricity. Most of the best shooters in F class don’t put any stock in it. My concentricity gauge does nothing but gather dust on the shelf. I encourage you to take best 10 pcs of ammo in terms of concentricity and shoot them at 300+ yards on the target against your worst 10 pieces of ammo (same exact load) and you be the judge yourself if concentricity means what you think it currently means. Good luck.
Dave

 

[cjc5062]

Are you shooting any better with all the upgraded stuff? I have always upgraded one thing at a time to see what I need and what is good enough for me. There are so many variables to becoming a really good shot. But it looks like you are off to a good start.

Have been getting very good standard deviation on velocities since upgrading. Consistently in the 4-5 fps standard deviation. But part of the fun is seeing just how good you can get the get the ammo.

 

[cjc5062]

Don’t get hung up on concentricity. Most of the best shooters in F class don’t put any stock in it. My concentricity gauge does nothing but gather dust on the shelf. I encourage you to take best 10 pcs of ammo in terms of concentricity and shoot them at 300+ yards on the target against your worst 10 pieces of ammo (same exact load) and you be the judge yourself if concentricity means what you think it currently means. Good luck.
Dave

Completely understood, and am not a newbie when it comes shooting. I know my form alone will make a bigger difference than runout. I probably won’t see any difference at 1000 yards regardless of runout. But I just enjoy trying to perfect the loading as best as possible.

 

[Chris Edmondson]

Are you turning your necks? To measure .0005" concentricity after sizing, then .004" after seating seems odd. Since concentricity gages measure from the outside, the only way I can imagine your loaded concentricity being so far different is if the neck inside is not coaxial, or not concentric with the outside.

 

[jackieschmidt]

There is nothing “straight” about most out of the box factory cases.
Fireform them, do your usual sizing operations and see if things improve.

 

[Straightshooter1]

Have been getting very good standard deviation on velocities since upgrading. Consistently in the 4-5 fps standard deviation. But part of the fun is seeing just how good you can get the get the ammo.

Like you, a big part of the fun for precision reloading is seeing how well I can produce every aspect of it to as consistent as possible. Recently, I watched a YouTube video from Little Crow Gunworks channel that summed things up really well as the conclusions aligned very well with the things I've leaned since starting precision reloading. For example, here's a graph that outlines things in the order of importance for its contribution to precision:

 

[ELR LVR]

Using Peterson Brass is a good step
I really like the consistent feel of their neck tension as opposed to Lapua.
Peterson feels like my tuned, turned and annealed Rem and Win Brass
Using a long Mandrel type neck expander will help to straighten out the necks prior to bullet seating
I use these from Hornady intead of a button.
.001" to .004" is actually really good
I like mine to be between .001"-.003"
All others I label as sighter or fouler rounds.

 

[dstoenner]

You didn’t say if you neck turn. That will get you the ultimate consistency. I also use a honed Forester full length sizing die witout the button.

1 and 2 total indicated runnout i have never seen to have any difference in accuracy. I use those for shots of record. 3-4 are just a smidgen bigger groups. I use those sighters. Anything else is foulers.

My normal distribution of Lapua brass is 50% 1’s, 30% 2’s and the rest are 3-5.

David

 

[Mark611]

The best way for me that I have found out to keep runout low is, I size my brass with a body die and neck size with a collet die, I usually end up with 1k or less doing it this way!

 

[6BRA]

I wouldn't be sure all bullets, even customs are concentric. My experience is that shorter bullets have considerably less variation than longer bullets. This may help to explain the PPC dominance for over 50 years. JMO and they are a dime a dozen. Runout at neck vs runout at bullet tip will be magnified.

 

[JMayo]

I wouldn't be sure all bullets, even customs are concentric. My experience is that shorter bullets have considerably less variation than longer bullets. This may help to explain the PPC dominance for over 50 years. JMO and they are a dime a dozen. Runout at neck vs runout at bullet tip will be magnified.

I came to say the exact same thing.
The 140's were allot worse than the 130's.
I concentrated on the necks of the cases.
I also made sure the bullet was standing straight up, best i could, when placing the seater on. Even dropped a few down the hole of the seater to see if it helped. (Nothing did with the burger 140's)

 

[Wesson]

I went down the road to reduce run-out.
I tried full lenght sizing and mandrel. It was OK but not great.
The best way, for me is decap the primer first with a decapping die.
Full lenght Resize with the expander as high in the die as possible, as one portion of the neck is still in the die as the bottom of the neck enter the expander. Everything is supported and straight.
Use a good lube inside the neck too.

I get 0 to .003" run-out and now as other, I don't use the concentricity gauge anymore...

 

[cavedweller60]

Like you, a big part of the fun for precision reloading is seeing how well I can produce every aspect of it to as consistent as possible. Recently, I watched a YouTube video from Little Crow Gunworks channel that summed things up really well as the conclusions aligned very well with the things I've leaned since starting precision reloading. For example, here's a graph that outlines things in the order of importance for its contribution to precision:

View attachment 1655959

I just saw this exact graph on a YouTube video last night. Is that your channel?

 

[ELR LVR]

I just saw this exact graph on a YouTube video last night. Is that your channel?

Interesting that I'm not seeing barrel quality on that graph
I would believe that a quality barrel holds more weight than cartridge selection
Only because I have seen what most would consider mediocre calibers
Shoot phenomenally when chambered in a custom barrel
a 223, 7 Mag, are just 2 calibers not considered particularly extremely accurate

 

[cavedweller60]

I'm not seeing barrel quality on that graph

In the video I watched, that was part of the topic. It was a multi part video in reference to creating an ELR rifle out of mid grade components, both for creating the gun and the ammo.

The barrel used, the brand slips my mind right now, wasn't a barrel your average ELR shooter would use. It wasn't a Bartlein, Brux, Krieger, etc....it was sort of a no name brand.

The chart listed each component and its importance to the final accuracy of the gun. The chart above was in relation to the ammo created.

 

[Steve Donlon]

When I was starting to do the same thing you are striving for, I was shooting 1/4 MOA but wanted to do better. I was not using Peterson or Lapua brass and had a chamber that needed my necks turned. Just doing that, got me to be able to cut my MOA in half. That might have not been the whole answer, or the reason why my groups got better, but for me, it allowed me to also give my concentricity gauge away. But that is far from being the whole answer. Seating the bullets straight is also a big part of it. Ever aspect at every step matters to some degree. Then you can see what does not matter for you. You need to be a good shot to start with in order to narrow down what you need to do next. Fundamentals will take you a long way.

 

[ELR LVR]

When I was starting to do the same thing you are striving for, I was shooting 1/4 MOA but wanted to do better. I was not using Peterson or Lapua brass and had a chamber that needed my necks turned. Just doing that, got me to be able to cut my MOA in half. That might have not been the whole answer, or the reason why my groups got better, but for me, it allowed me to also give my concentricity gauge away. But that is far from being the whole answer. Seating the bullets straight is also a big part of it. Ever aspect at every step matters to some degree. Then you can see what does not matter for you. You need to be a good shot to start with in order to narrow down what you need to do next. Fundamentals will take you a long way.

This is good info.
Being a good shot, but also having at least 1 very accurate rifle you know shoots in the 1's to be able to always gauge yourself on.
If I happen to not be putting them in 1 hole with that 1 rifle
then I know I'm rusty and there is no use fiddling with accuracy on another rifle until I've warmed up a little.

 

[K22]

Of course, precision reloading is vital for the accuracy standard you have established but you may find the most significant variable is the shooter and environmental conditions.