Concentricity Gauge Arrived!!!

[markg]

My Concentricity Gauage arrived this week. I set it up tonight and I learned a few things.

1) Lapua Brass is amazing (well more confirmed than learned) I resized some of my once fired 6.5x47 Lapua brass and measured every 5th piece. All of them were 1/1000th or less runout. This also means that my redding neck bushing die is also very very tight in its tolerances. It also confirms that my Press does not affect my ammo to any significant amount. I am pretty happy right now.

2) After testing some 308 ammo I made with lapua brass I learned that this ammo has less than 2/1000ths of runout. This means the brass is great, the bullet seater is great and the bullets themselves are well made. It also shows that both the resizing die and seating die are working well.

3) After testing some 7mm Rem mag hunting ammo I learned that it is not as well made as my target shooting ammo. It had 3 or 4/1000th of runout. I am using Nosler Brass and a redding full length sizing die. I have yet to determine where the runnout is occuring as I have no fired brass to resize and measure.

I am pretty happy with the new toy, I think it will provide me with alot of useful information about the quality of my reloading. I think I might also try and test some bullets and see how they look.

[Dick284]

Are you measuring your run out on sized cases or cases after you've seated your bullets?

[markg]

my 6.5 measurements are on sized cases

my 308 measurements are on the necks of ammo that has a powder charge and the bullets are seated and ready to fire.

[gitrdun]

Which brand of gauge are you using markg? I use the Forster with a few of my own mods, such as a digital indicator for one.

[Bushrat]

Originally Posted by markg

my 6.5 measurements are on sized cases

my 308 measurements are on the necks of ammo that has a powder charge and the bullets are seated and ready to fire.

Measure the run out on the loaded bullet.

[markg]

I am just at the testing phase of having a new toy and investigating lots,of things about the reloading process.

Thanks for the advice on testing the loaded bullet.

[lclund1946]

I use a Sinclair gage with a Mitutoyo dial indicator that measures 0.0001".
I have measured a lot of case necks on new brass, neck turned brass, fire formed brass and brass formed with my 20 EXTREME Dies. One thing I have learned is that case neck run out has been very similar with all brands of brass with some lots having the advantage. For example I just measured 10-223 Lapua Match brass, out of the box, and found 2 with about 0.0005" and 8 with 0.0025" neck run out. I measured one that I had sized down to 20-223 with my Hornady EXTREME die and found it had 0.003" neck run out. Of the 10 that I turned, before forming with the 20 EXTREME die, 2 had 0.0005" and 8 had nearer 0.0015" run out on the necks.

I checked 10 Winchester 222 Rem brass and found 2 with less than .001", 2 with 0.003+ and 6 with 0.0025" neck run out. I checked 20 of these Winchester brass after turning the necks and forming to 20 EXTREME and found them to average about 0.0005", with some as low as 0.0003" and one as high as 0.0008" neck run out. I measured these 20 with 39 Blitz King bullets and bullet run out varied from a low of 0.0004" to a high of 0.0033" with an average of less than 0.002". Another thing I have learned is that neck run out does not conform to bullet run out.

The best lot of brass that I have had in my 20 EXTREME is 100 Remington 222 brass. Necks did not require turning and bullet runout, with 40 V-Max, was exceptional with 95% less than 0.0015". Actually 50 % were less than 0.0006" with a couple at 0.0045". This lot of brass has been fired 5 times and still measures the same at the shoulder and base as it did when it came out of the bag in spite of chasing the 40 V-Max at about 3640 fps.

[gitrdun]

Great post Iclund1946. I always appreciate your attention to details and learning from your experiences.

[HW223]

Originally Posted by lclund1946

I use a Sinclair gage with a Mitutoyo dial indicator that measures 0.0001".
I have measured a lot of case necks on new brass, neck turned brass, fire formed brass and brass formed with my 20 EXTREME Dies. One thing I have learned is that case neck run out has been very similar with all brands of brass with some lots having the advantage. For example I just measured 10-223 Lapua Match brass, out of the box, and found 2 with about 0.0005" and 8 with 0.0025" neck run out. I measured one that I had sized down to 20-223 with my Hornady EXTREME die and found it had 0.003" neck run out. Of the 10 that I turned, before forming with the 20 EXTREME die, 2 had 0.0005" and 8 had nearer 0.0015" run out on the necks.

I checked 10 Winchester 222 Rem brass and found 2 with less than .001", 2 with 0.003+ and 6 with 0.0025" neck run out. I checked 20 of these Winchester brass after turning the necks and forming to 20 EXTREME and found them to average about 0.0005", with some as low as 0.0003" and one as high as 0.0008" neck run out. I measured these 20 with 39 Blitz King bullets and bullet run out varied from a low of 0.0004" to a high of 0.0033" with an average of less than 0.002". Another thing I have learned is that neck run out does not conform to bullet run out.

The best lot of brass that I have had in my 20 EXTREME is 100 Remington 222 brass. Necks did not require turning and bullet runout, with 40 V-Max, was exceptional with 95% less than 0.0015". Actually 50 % were less than 0.0006" with a couple at 0.0045". This lot of brass has been fired 5 times and still measures the same at the shoulder and base as it did when it came out of the bag in spite of chasing the 40 V-Max at about 3640 fps.

Properly turned brass will have less than .0002 run out , if not ,you need a better process , if the chamber is decent fired brass will measure zero or very close , the run out usually comes from various things in the sizing and seating process ,concentriciry guage is a great tool for checking and tracking down irregularities ,

[markg]

I find that I dont have to turn my brass when I use Lapua. In fact I dont even own a brass turning lathe. I can see using one then you can shoot cheaper brass and not worry if you loose a piece or wreck a piece.

[qwert]

Originally Posted by markg

I find that I dont have to turn my brass when I use Lapua. In fact I dont even own a brass turning lathe. I can see using one then you can shoot cheaper brass and not worry if you loose a piece or wreck a piece.

Precision is all about consistency.
Consistent neck wall thickness circumferentialy will assist concentric bullet release, and prevent localized work hardening (which will be greatest in thin sections, and lead to longitudinal splitting) when resizing.
Consistent neck wall thickness case to case will help consistent neck tension, powder ignition, pressure build, and concentric bullet release, all of which will reduce vertical POI variation.

Lapua brass is better than most, but it is far from perfect.

I resisted neck turning until I realized it was the key to uniform neck tension. IMHO it is especially required when using neck bushing dies without an internal expander ball.

I measured neck wall variation as best I could using a dial indicator, but it was not until I could actually see the variation when skim turning that I realized just how much variation there was both laterally and longitudinally.

Neck turning is not a magic bullet and will not fix all problems, but IMHO it is an essential step in case prep.
It will also reduce the number of expensive neck bushing sizes needed.

I suspect that a Collet NK die may tend to move brass from thick to thin areas, but this would be a gradual process and the case life may be consumed before complete.

Good Luck, YMMV.

[fps plus]

It was an eye opener hope much bullet run out affected accuracy!

[Full Curl Earl]

Are we talking 2 tenths of a thousandth here or 2 thou.

[Dick284]

Originally Posted by Full Curl Earl

Are we talking 2 tenths of a thousandth here or 2 thou.
Those are amazing results on a brass product either way, but I am curious about about the calipers measuring in the tenth of a thousandth. It must be digital is it?

It isn't a set of calipers being used.

https://youtu.be/HTkjkhKoE9U

[Full Curl Earl]

Lol misread then edited, but you got it first.

[Pathfinder76]

I've measured runnout long enough that in most cases we are pole vaulting over mouse terds. Yes it effects accuracy, but what is the end goal? In a hunting rifle find dies that make straight ammo and be done with it. Also, shoot your ammo. Mark cases that produce flyers. That case will likely produce flyers again. Toss it if it does.

[Dick284]

Originally Posted by chuck

I've measured runnout long enough that in most cases we are pole vaulting over mouse terds. Yes it effects accuracy, but what is the end goal? In a hunting rifle find dies that make straight ammo and be done with it. Also, shoot your ammo. Mark cases that produce flyers. That case will likely produce flyers again. Toss it if it does.

You are most likely correct here Chuck.

But Mark is a long bomber hopeful.
He's buying all the gadgets and widgets that will bring him into the annals shooting prominence.

It's different than hunting dontchyaknowit.

[markg]

I am in fact a long range wannabe. I look forward to the day when I can hit something at 1k consistently. I am a long way off from that both literally and figuratively.

Right now I am just throwing money and practice at the problem.

[markg]

I guess a guy could have worse bad habits then practicing shooting. I think a drug addiction would be cheaper though.

[HW223]

Originally Posted by chuck

I've measured runnout long enough that in most cases we are pole vaulting over mouse terds. Yes it effects accuracy, but what is the end goal? In a hunting rifle find dies that make straight ammo and be done with it. Also, shoot your ammo. Mark cases that produce flyers. That case will likely produce flyers again. Toss it if it does.

I agree, in a hunting or general plinking situation it's overkill , in competition Where your trying to put them all in the same hole it's just one of the many things that has to be right .

[lclund1946]

Originally Posted by markg

I find that I dont have to turn my brass when I use Lapua. In fact I dont even own a brass turning lathe. I can see using one then you can shoot cheaper brass and not worry if you loose a piece or wreck a piece.

Lapua Brass is much more consistent in neck wall thickness than most other brass and generally will produce rounds with less run out than Winchester or Remington. This is because the inconsistent neck tension due to varying neck thickness on a case is largely what causes run out. I used to buy into the idea that you could reduce bullet run out by seating the bullet part way and then turning before fully seating bullet. I did extensive testing and found that run out remains orientated the same, no mater how it is seated. I also found that excessive run out can be mitigated but not eliminated.

I do not have to turn 222 Winchester and Remington brass necks on my 20 EXTREME as it is designed to be no turn with this brass that have thinner necks than 222 Lapua Match brass which must be turned. In fact the Lapua brass necks really have far too much neck tension if not turned to come out at about 0.012". This is a problem with the 20 VarTarg and 20 Tactical and to a lesser extent the 20 Practical when forming from Lapua Brass. I also have to turn the necks if I use 223 brass to form brass my 20 EXTREME. I do turn the necks on 222 Winchester brass but only to even up neck tension and mitigate bullet run out. I have taken time to compare fully prepped (weight sorted, neck turned, primer pockets & flash holes reamed etc.) and really found that it did not make much difference over brass formed right out of the bag. These targets show that for my Varmint Cartridge it is really unnecessary as wind is a much bigger factor:
[IMG][/IMG]

[HW223]

Like I said plinking , it doesn't matter but won't hurt , putting bullets in the same hole , it's a must

[markg]

What do you use for bullet seating iclund? I find that when I use a micrometer die with case sleeve that it really reduces runout. I wonder what has more impact on runout the quality of the die or neck turning?

[gitrdun]

My experience is that I get extremely low run-out by first fire forming the cases in the intended rifle. Then run them through my collet die. After that, I turn the necks lightly, adjust the cutting tool just enough to get a full skim on the neck. Then I run them through the collet die once more. I actually dedicate as much time and effort for my hunting ammunition. It may not be desirable for others, but my personal way of thinking is that if I can turn out precision ammo for target shooting, why not do likewise for my hunting rounds. I roll much less hunting rounds that I do target rounds. I'm happy each year to have 20 precision rounds to hunt with. I realize that this does not fall into the needs of other hunters, and that's OK. We all take different approaches to our intended end results.

[lclund1946]

Originally Posted by markg

What do you use for bullet seating iclund? I find that when I use a micrometer die with case sleeve that it really reduces runout. I wonder what has more impact on runout the quality of the die or neck turning?

I use my Hornady Custom Grade 20 caliber Seating Die which will seat bullets in all 20 Caliber cartridges. It has a sleeve which helps hold the bullet without catching my fingers and I have added a Micrometer to adjust seating depth as I use the same die for many different loads. I have loaded many thousands of rounds and run out has been as low as 0.0003" with the majority being less than 0.0015". With Winchester and Remington brass I get about 2-5% that have between 0.0015" and 0.0045". I contribute this mostly to uneven neck thickness, which continues down through the shoulder and body, causing uneven tension on the bullet. As I stated turning necks will help even up neck tension and lessen run out but as Chuck suggested the best way to fix bad cases is to chuck them.

I do not think that having a sleeve, that you are talking about, helps as it would have to be cut to exactly fit your brass and be in perfect alignment to get less than 0.0005" run out. This is not possible unless you get is custom made. I know that manufacturers can slip up and make a bad run of dies but in fact they all make very good quality dies. Some marketing experts have led people to believe that their dies are better quality than others but the fact is the only difference is usually price.

[260 Rem]

I have never measured run-out (I know I should) ...but can say my best downrange results are achieved using Wilson In-line Seaters....brass resized with Redding S dies with bushings...necks lightly turned.

[qwert]

Originally Posted by gitrdun

My experience is that I get extremely low run-out by first fire forming the cases in the intended rifle. Then run them through my collet die. After that, I turn the necks lightly, adjust the cutting tool just enough to get a full skim on the neck.
snip

This is my exact procedure for case prep, except that I only turn for 90-95% skim cut.

I also first fireform using a heavy lead boolit jammed hard into the lands (I could not extract it without getting a magazine full of powder) and reduced charge of SR4759 or similar.

I have Redding Competition dies, but actually prefer the Lee Collet neck dies, until I need to bump the shoulder using a Redding body die & Comp shell holder.

IMHO, the Redding Comp neck bushing dies are best for partial length sizing of the neck, to create a precise lip which holds the bump at the bullet base very precisely and (according to the 'Secrets of the Huston Warehouse') is the key to maximum precision (and well beyond my ability). I do have carbide ball expanders for my Redding Comp dies, but have yet to complete needed testing to determine effective utilization.

Good Luck, YMMV.

[qwert]

Originally Posted by lclund1946

I use my Hornady Custom Grade 20 caliber Seating Die which will seat bullets in all 20 Caliber cartridges. It has a sleeve which helps hold the bullet without catching my fingers and I have added a Micrometer to adjust seating depth as I use the same die for many different loads.
snip
I do not think that having a sleeve, that you are talking about, helps as it would have to be cut to exactly fit your brass and be in perfect alignment to get less than 0.0005" run out. This is not possible unless you get is custom made. I know that manufacturers can slip up and make a bad run of dies but in fact they all make very good quality dies. Some marketing experts have led people to believe that their dies are better quality than others but the fact is the only difference is usually price.

I have some Hornady seaters and like their sliding case/bullet guide feature and ability to use with several cartridges of the same caliber, (IMHO they are a significantly better design then the RCBS style seaters), however they are not in the same class as the precision fitted Redding Comp case guides which are actually finished to such fine tolerances as to be air tight. They are in fact 'cut to exactly fit' (admittedly only SAAMI std and not fireformed) brass.

Redding Comp dies ARE expensive, and for very good reasons, (that do not extend to their common basic RCBS design dies that ARE VERY well built but still (IMHO) an obsolete design). IMHO, their function and accuracy can only be compared with the Wilson straight line seaters.

Lee Collet Neck dies do not have NEARLY the quality or finishing of the Redding dies, their advantage is their simple and effective design, which works VERY well.

Good Luck, YMMV.

[Pathfinder76]

Originally Posted by 260 Rem

I have never measured run-out (I know I should) ...but can say my best downrange results are achieved using Wilson In-line Seaters....brass resized with Redding S dies with bushings...necks lightly turned.

I have found the same.

[markg]

Redding compettiotion seating dies are what I use. I also have a Whidden set that are also very nice. I do like they way they hold the brass when seating the bullet.