Concentricity

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Jason72
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Concentricity

#1 Postby Jason72 » Sat May 30, 2020 8:24 pm

Hi

A question to F-class/open shooters.
Is it worthwhile adjusting the run-out of a projectile with a concentricity tool such as a Hornady? Does it improve accuracy?

Cheers
Jason

Rich4
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Location: Chinchilla

Re: Concentricity

#2 Postby Rich4 » Sat May 30, 2020 8:49 pm

Hornady runs on the rim not the body, however I’ve had useful results straightening factory ammo in conjunction with batching on bto and weight, but not for serious open use and the time involved is no less than reloading #-o

Jason72
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Joined: Sat Feb 10, 2018 5:23 pm

Re: Concentricity

#3 Postby Jason72 » Sat May 30, 2020 9:07 pm

Hi Rich

Was talking about the Hornardy concentricity gauge which straighten the projectile so it is parallel to the casing.
Do you,think it is worth taking the time to do this and does anyone think it improves accuracy?

Cheers
Jason

GSells
Posts: 678
Joined: Sun Aug 13, 2017 11:04 pm

Re: Concentricity

#4 Postby GSells » Sat May 30, 2020 10:04 pm

Jason72 wrote:Hi Rich

Was talking about the Hornardy concentricity gauge which straighten the projectile so it is parallel to the casing.
Do you,think it is worth taking the time to do this and does anyone think it improves accuracy?

Cheers
Jason

I think I believe you measuring run out of your rounds and checking how good your reloading gear is ?
I have a Sinclair runout gauge I use now and then just to check how much run out on my necks . Then the runout of the projectile seated in the case .
3 thou max runout and yes it’s worth doing . But I’ve seen lots of x’s and 600 yds on 7 thou unfireformed cases ! But that’s rare !

I’ve been using Berger Projectiles , umm never sorted them by run out and not needed . Worth more by sorting them base to metplate and then base ( within 3 thou ) to ogive ( 1 thou ) .
Regards Graham Dalby / Tara RC .
Ps truth I’m missing competing! Hope I know which is the dangerous end and not so and where the trigger is when we get back lol!

Jason72
Posts: 29
Joined: Sat Feb 10, 2018 5:23 pm

Re: Concentricity

#5 Postby Jason72 » Sun May 31, 2020 7:16 am

Thanks for that information Graham, very useful.
Ha ha yes mate, will be a bit of dust to brush off gear when we get back to the mound.

Cheers
Jason

Rich4
Posts: 224
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Location: Chinchilla

Re: Concentricity

#6 Postby Rich4 » Sun May 31, 2020 7:58 am

Yes I know the tool you are talking about, I use a forster (non adjustable vee) because I got it cheap, a Sinclair or similar would be better to adjust where you are measuring from as the best place to run is on the body I feel, the hornady does not have that option, non concentric rims are more common than you’d think, a timber block can be used as an anvil to straighten them with thumb pressure, you’ll soon get a feel for how much is needed
Yes I’ve proven it helps with Factory Ammunition, I only shoot 0.002 tir or better otherwise I straighten it, I do believe that the best result is in headspace consistency ( the one between my ears)

Jason72
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Re: Concentricity

#7 Postby Jason72 » Sun May 31, 2020 10:04 am

Ha ha true Rich, doesn't matter how much we prep a case if we have poor technique and can't read the wind.

Gyro
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Location: New Zealand

Re: Concentricity

#8 Postby Gyro » Sun May 31, 2020 10:43 am

Rich4 wrote:Yes I know the tool you are talking about, I use a forster (non adjustable vee) because I got it cheap, a Sinclair or similar would be better to adjust where you are measuring from as the best place to run is on the body I feel, the hornady does not have that option, non concentric rims are more common than you’d think, a timber block can be used as an anvil to straighten them with thumb pressure, you’ll soon get a feel for how much is needed
Yes I’ve proven it helps with Factory Ammunition, I only shoot 0.002 tir or better otherwise I straighten it, I do believe that the best result is in headspace consistency ( the one between my ears)


I thought I was the only one in the world who straight away thought that referencing a case off the rim is probably not smart. I told a guy I know on the range once who had one of those that his Hornady tool was likely flawed and he got very pissed off with me to say such things !

Steve N
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Location: Gippsland Victoria.

Re: Concentricity

#9 Postby Steve N » Sun May 31, 2020 7:58 pm

I have one of those tools and if they show a problem with the concentricity of a round then I would put it aside if shooting long range. The round can be adjusted to show lower runout and it might not help much but probably doesn't hurt.

wsftr
Posts: 163
Joined: Tue Jan 30, 2018 12:58 pm

Re: Concentricity

#10 Postby wsftr » Mon Jun 01, 2020 8:49 am

Jason72 wrote:Hi Rich

Was talking about the Hornardy concentricity gauge which straighten the projectile so it is parallel to the casing.
Do you,think it is worth taking the time to do this and does anyone think it improves accuracy?

Cheers
Jason


In principle I'm not a fan of adjusting concentricity once loaded. To be fair I have never tested it but the principle goes against consistency of neck tension being a key factor in precision so IMO straightening a seated a projectile is a bit like fighting yourself.
Concentric ammo is important - get tools that correctly measure concentricty and then work on loading technique, equipment so that they are straight to start with.
I end up with < .002" run out and for my purposes that is fine with other factors being a bigger determinant in x count IMO, YMMV.

Jason72
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Joined: Sat Feb 10, 2018 5:23 pm

Re: Concentricity

#11 Postby Jason72 » Sun Jun 28, 2020 5:24 pm

Well you were spot on Graham, I didn't realise how much difference there was in Berger 155.5's.
I purchased a Shars comparator from BRT to check the base to ogive. There was 5 thou difference in a 100 pack of projectiles (I measured 2 x 100 packs). First pack had 51 of the same measurement, 34 with 1 x thou less, 8 with 1 x thou more and the remaining 6 were what I call odd bods, 1/2 x thou either side of the zero.
The next 100 had similar results.
The Shars comparator works well, very accurate, very repeatable results and easy to use.

Cheers
Jason

KHGS
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Re: Concentricity

#12 Postby KHGS » Sun Jun 28, 2020 6:30 pm

Jason72 wrote:Well you were spot on Graham, I didn't realise how much difference there was in Berger 155.5's.
I purchased a Shars comparator from BRT to check the base to ogive. There was 5 thou difference in a 100 pack of projectiles (I measured 2 x 100 packs). First pack had 51 of the same measurement, 34 with 1 x thou less, 8 with 1 x thou more and the remaining 6 were what I call odd bods, 1/2 x thou either side of the zero.
The next 100 had similar results.
The Shars comparator works well, very accurate, very repeatable results and easy to use.

Cheers
Jason

Do you know what .005" is in context with a bullet length of over 1.000" (it's about the thickness of a piece of notepaper) ????? It is a small %. However in the context of said bullets diameter, that would be a different matter!!! For the record I do not measure loaded round runout either, I use proper dies set up correctly, my loaded rounds average under .003". I have most of the gismos required to do all this stuff, most gathering dust. I have done and do a fair bit of testing, ananalys of and rejecting of some ideas. Having said that it is good to have an inquiring mind, but we should not accept what is written (advertised) blindly. :) :)
Keith H.

GSells
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Re: Concentricity

#13 Postby GSells » Sun Jun 28, 2020 7:30 pm

Jason72 wrote:Well you were spot on Graham, I didn't realise how much difference there was in Berger 155.5's.
I purchased a Shars comparator from BRT to check the base to ogive. There was 5 thou difference in a 100 pack of projectiles (I measured 2 x 100 packs). First pack had 51 of the same measurement, 34 with 1 x thou less, 8 with 1 x thou more and the remaining 6 were what I call odd bods, 1/2 x thou either side of the zero.
The next 100 had similar results.
The Shars comparator works well, very accurate, very repeatable results and easy to use.

Cheers
Jason

Base to metplate is most important within 3 thou . Or you can go 5 thou but in rising or falling lots and load in that manner. This also has a large impact on seat depth and harmonics . Rarely I do base to ogive and in 1 thou lots and only in a queens .

Glad to see you are enjoying the sport ! Might see ya on the mound one day mate !! Regards Graham.

GSells
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Joined: Sun Aug 13, 2017 11:04 pm

Re: Concentricity

#14 Postby GSells » Sun Jun 28, 2020 7:43 pm

Just continuing on , in Berger 180’s I’ve seen 140 thou in base to metplate overall lengths . You can only imagine what that may do to seat depth and variable bc at 1000 yds . Doing with in 5 thou and Sd of 5 of 7 or more shots wii enable you to get a high x count and half x ring elevation in stable conditions. Base to ogive I think is a waste of time with Bergers in 7 mm 180’s anyway in my experience. And keith is right . Be careful not to fall in the trap of overthinking it ! At Qld teams I second guessed myself so much that the Captain had to say a few words and calm me down !

I do need to have more faith in my gear and focus on shot by shot ! Only way one is going to come out on the pointy end ! Lock yourself in your own little bubble .

Cam Mac my Mentor use to say “ if you can hear people talking on the mound behind you . You are not focusing on the conditions enough “ .
And it’s so true ! It’s simple ! Shot by shot that is it ! And I say that to myself more than anybody reading this !

RDavies
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Re: Concentricity

#15 Postby RDavies » Wed Jul 01, 2020 10:27 pm

I have a loaded round straightening device which i intend to donate at the end of day 2 of my next Queens shoot to whoever is ahead of me. I have only used it once and it has been gathering dust since. It seems that when straightening bent rounds, the neck tension changes quite a bit, which hurts accuracy at long range. It is quite a while since I have actually measured loaded round runout as I found that with the dies and reloading process I use, runout was usually not too bad and not likely to cause issues. If I buy any new dies, I might brush the dust of my checking tools and check that runout is not excessive.


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