General question on bullet concentricity

[rcflyer]

I have been looking at a multitude of videos on YT from professional level shooters and producers. In those videos, I have seen them refer to varying levels of bullet/neck concentricity. Some have referenced .0005", some .003", and some have said that up to .005" doesn't really affect bullet accuracy. What I am not seeing is what their reference is measured from. I have Sinclair and Hornady gauges, and I can't see how they can measure the same values. First, the Hornady cannot measure neck runout, and since it pins the nose and base of the loaded round to its center axis, I think any runout I measure would be half (or approximately half) of the runout based on using the case as a reference as does the Sinclair.

I run an Area 419 press, LE Wilson FL bushing sizer and 21st Century mandrel dies. Over the years, I have gone from a Rock Chucker to MEC Marksman to a Forster Co-ax press and now to this Area 419. My seating die is a RCBS matchmaster seating die. The reason I am asking this is that the best reading I can observe on the Sinclair gauge is +/- .002, which I interpret to be a total runout of .004". Occasionally, I will resize a case and it will be in the neighborhood of .006 to .008 total, and I do everything exactly the same during the process.

What am I doing wrong that is giving such high values, and in general, does it really matter what I am observing? Am I being overly anal about this?

Thanks

 

[DShortt]

IMO, the Hornady concentricity tool is useless.
The Sinclair is at least based off the case itself.
I have no opinion on if run-out is relevant because thus far, I've found other things to work on such as mirage and wind.

 

[rcflyer]

IMO, the Hornady concentricity tool is useless.
The Sinclair is at least based off the case itself.
I have no opinion on if run-out is relevant because thus far, I've found other things to work on such as mirage and wind.

Thanks. I know there are a ton of other things that influence accuracy. What my question was aimed at is the reloading process itself. I feel like I have invested in good equipment, and have tailored my reloading process as much as I can to those YT guys like Gavin, Eric, F-class John, etc. I am slowly changing my components (particularly brass) to something other than range pickup, or once fired factory brass that I have fired through my rifle. I anneal, and collet size and mandrel expand the case necks, to try to insure consistent interference fits (aka, neck tensions) but somehow as careful as I try to be, I see inconsistencies that I would like to get rid of.

 

[Rwfish]

When I’m doing my initial checks on a Sinclair I like to check the case at the contact point just below the shoulder first. If that is out .0005” then that is the best your neck can be. I then check the neck. I’ll then check the neck again after seating the bullet to be sure things aren’t moving, then I’ll check the bullet. I don’t do this to every round. Just a few to insure I know what’s happening thru the process. So, if the case is out .0002” the neck another .0005” and the bullet another .0002” well, it all adds up but you know why…

 

[Webster]

Thanks. I know there are a ton of other things that influence accuracy. What my question was aimed at is the reloading process itself. I feel like I have invested in good equipment, and have tailored my reloading process as much as I can to those YT guys like Gavin, Eric, F-class John, etc. I am slowly changing my components (particularly brass) to something other than range pickup, or once fired factory brass that I have fired through my rifle. I anneal, and collet size and mandrel expand the case necks, to try to insure consistent interference fits (aka, neck tensions) but somehow as careful as I try to be, I see inconsistencies that I would like to get rid of.

Shoot them and you will know if it makes a difference.

 

[Coyotefurharvester]

But you use a mandrel step after sizing, so what is the run out in the case after the mandrel(last brass step before seating)? Does this value change after seating? Maybe at least give you a cause, whether it matters or( not to me as the chamber is straight).

 

[JEFFPPC]

So there are 6 posts on this thread. I wonder how many of the six Never shoot without wind flags during load development. If its any I would be surprised. If your using good equipment and components with a quality rifle I think your chasing ghosts. I think your efforts could be spent better elsewhere. Not trying to down what your doing but trying to point you in some more productive direction.If your using range brass your contributing to your problems.

 

[Bill Norris]

When I read threads pertaining to runout I always remember the test that Erik Cortina done some years back when he test some rounds with up to .015 runout and saw no difference in the groups. Some say it does matter but I have not seen any differences in my testing. One past long time F-class shooter once said if the shooter thinks it matters then it does within his or her program.

 

[Someone online]

I personally did a runout test two weeks ago. One batch runout of +-.003 or less and the other batch greater than +-.003 (some as high as .010). There were over 0 rounds in each batch. Measured at the ogive of the bullet and concentric to the case using the rcbs concentricity gauge.

Results were a nothingburger. No difference in group size. Maybe my shooting sucked or my rig was too inaccurate to determine this. But for my rifle that refuses to do better than 1moa on a good day, it made no difference. Maybe it makes a difference if it was a .5 moa gun?

 

[jpjulian]

Do. Not. Fret. About. It. Just. Go. Shoot........... Have fun shooting......

 

[Ranger188]

If you have good reloading equipment and some knowledge of reloading,
throw away those worthless tools.
It's been tested many times and doesn't seem to make much difference.
You have many other things that WILL make a difference to worry about.
That one is way way on the bottom of the list.
If you have a problem, something else is usually causing that issue.

 

[boltfluter]

Why would you use range pick-up brass and expect benchrest results? This makes absolutely no sense. You have first rate loading tools to do the job, now go out and get some quality brass. You may be pleasantly surprised how all of the run out issues are more or less gone. Sometimes the cart gets ahead of the horse. Good luck and keep us posted.
Paul

 

[K22]

You did not mention your shooting discipline or if you did, I missed it.

In my experience, wind, mirage, temperature, and shooter variability are the overriding significant factors affecting precision / accuracy assuming you have done some reasonable load development, have a capable load, a sound rifle / scope system, and a sound shooting platform which is discipline dependent.

With regards to the load, I have found that bullet selection, first, and powder selection, second, are the most significant factors.

When you see a wide range of opinions from experienced shooters on an issue that should be a "red" flag that there may be no definitive answers. I believe concentricity is one of those issues.

 

[Fuj]

Arguably big difference in disciplines. I'll note the mentioning of Eric
Cortina. Not knowing What he used in his testing, I will assume he
was using a long freebore, and loaded long where anything loaded
sideways is getting straitened out in the chambering process. In short
porch BR, many are jamming into a no free bore chamber, and ammo
is generally seated with an inline die with arbor press.....I'll be the odd duck
here, because I use modified long mandrel collet dies to seat. My ammo
is plus/minus .001" as seated using an ancient refurbished RCBS JR. press.

 

[SKWERLZ]

When I read threads pertaining to runout I always remember the test that Erik Cortina done some years back when he test some rounds with up to .015 runout and saw no difference in the groups. Some say it does matter but I have not seen any differences in my testing. One past long time F-class shooter once said if the shooter thinks it matters then it does within his or her program.

I’d say it matters a LOT less with a quality barrel with fairly tight FB diameter.


In sloppy n cheap barrels I tried years ago it did consistently make a difference.

 

[rcflyer]

Why would you use range pick-up brass and expect benchrest results? This makes absolutely no sense. You have first rate loading tools to do the job, now go out and get some quality brass. You may be pleasantly surprised how all of the run out issues are more or less gone. Sometimes the cart gets ahead of the horse. Good luck and keep us posted.
Paul

I guess I need to clarify a little more. I am not questioning the accuracy I am getting out of my guns, as I realize there are so many variables that go into range dynamics. My reference to range brass, was just simply that I had gotten a box of 5.56 brass that a buddy had picked up. I use Starline, Hornady, and now Alpha in my 6 ARC. Lapua doesn't natively make 6 ARC brass, but they do make 6.5 Grendel and 220 Russian. I have reloaded and transformed some of the Starline cases into 6 ARC, but mosty, I am using virgin Starline and Hornady. I just purchased a box of the Alpha 6 ARC, and that is what led to my original post. The runouts I see are on virgin Alpha brass, that are mandrel sized to .002 interference fit with my ELD-VT Hornady bullets and seated with the RCBS Matchmaster seating die. I am not using beat up brass at all.

 

[TxBowHunter409]

So there are 6 posts on this thread. I wonder how many of the six Never shoot without wind flags during load development. If its any I would be surprised. If your using good equipment and components with a quality rifle I think your chasing ghosts. I think your efforts could be spent better elsewhere. Not trying to down what your doing but trying to point you in some more productive direction.If your using range brass your contributing to your problems.

I was going to say that latter part myself. To have spent that much money buying good equipment, and be that concerned with run-out and concentricity, just to turn around and use range brass? That makes zero sense to me. I've only been reloading less than a year, and buying Lapua brass right off the bat was within the first 5 items I initially purchased.