Concentricity .. how important?

[DartonJager]

Bigedp51,
Thanks for the reply. Right now and for at least the next 5-7 years I will be limited to shooting my factory rifles as I wont be able to afford building a true long range rifle till my boys are out of collage. That's not to say I wont convert one of my rifles to a long range platform, but it the only major change besides optics would be a better stock and glass bed job.

I would also likely upgrade to Norma brass. I would likely buy the Sinclair and Redding gauges you recommend I already have invested in Forster BR dies and Redding body only sizing dies for most of the rifles I reload for and would simply get those 3 dies for the few I don't have them for now.

Thanks,
Arthur.

 

[J E Custom]

I could just SCREEEEEEEEEAM, and I'm not kidding. I strive to always produce the most accurate reloads I can but it has become painfully clear to me doing so almost demands a considerable expenditure of money. It would seam my RCBS RC press needs to be replaced with a Forester COAX press, and I need at the VERY LEAST to invest in a Redding case neck gauge and a Sinclare concentricity gauge as well as Forester BR FL sizing and bullet seating dies for all of my reloading of rifles. And my ammo is only as good as the firearm I put it in and all of my rifles are stone stock factory so even if I produce ammo with >.003" run out if my rifles chambers are less than perfect they will likely negate my accuracy potential of my ammo even if near perfect.

It's times like this where ignorance could almost be looked upon as bliss.

You are right about the factory rifles not being up to the task and to achieve this level of precision you will need a custom rifle with the best parts most of the time. But don't despair, The equipment you have will do a good job if you are careful. It just won't load perfectly concentric ammo every time.

I was very happy with the same setup for many years but just wanted better accuracy and started trying different ways to understand what it took to improve it.

If you accuracy is good and satisfies you, then there is little need for these pieces of equipment, then everything helps. At one time I was happy with 1/2 MOA groups. then I wanted 1/4 MOA, and that took lots of effort. When that became possible, I thought why not go for 1/8th MOA. Things got very hard then. And now I strive for 1/10th MOA (That is the toughest neighborhood there is, and not always possible with a hunting rifle. But it helps the accuracy because you cannot leave any stone UN-turned.

There was also the mention of the ejector plunger pushing the case off center in the chamber. And It will if the case is sized to much, And also the reason I try not to size the case body at all unless I start having troubles chambering The ejector has enough force to produce false head space readings if not removed so it could definitely push the cartridge off center If the cartridge doesn't fit the chamber perfectly. If you Full length size, the process/philosophy of seating the bullet to contact the lands is a good way to minimize this misalignment.

J E CUSTOM

 

[bigedp51]

The ejector does not create "false headspace", both the firing pin and ejector with push the case forward by the amount of shoulder bump. The amount of shoulder bump is your head clearance when the cartridge is chambered.

And full length resizing eliminates or minimizes the effects of a warped case.

Reloading: Partial Neck Sizing
by German A. Salazar
http://riflemansjournal.blogspot.com/2010/06/reloading-partial-neck-sizing.html

"Now the last scenario, a full-length sized case in which the neck is also fully sized. There is clearance at the neck and in the body of the case, the closest fit anywhere is the bullet in the throat. If the neck to bullet concentricity is good (although it needn't be perfect), then the bullet will find good alignment in the throat and the case body and neck will have minimal influence. Let's not forget that the base of the case is supported by the bolt face or the extractor to a certain degree as well; this is yet another influence on alignment. As you can see, there are several points from base to bullet that can have an effect. My procedure is to minimize the influence of those that I can control, namely the case body and neck, and let the alignment be dictated by the fit of the bullet in the throat and to some extent by the bolt's support of the base. Barring a seriously out of square case head, I don't think the bolt can have a negative effect on alignment, only a slightly positive effect from minimizing "case droop" in the chamber. Given that a resized case will usually have a maximum of 0.001" diametrical clearance at the web, this isn't much of a factor anyway."

When reading the posts here you must distinguish from the die hard neck sizing only reloaders from those who full length resize.


STOP NECK SIZING YOUR BRASS!!!!
By Erik Cortina Team Lapua USA



Below click on image to enlarge.

 

[fisherman983]

28 Nosler
28 Nosler
6.5 SLR
.260 Rem
.264WM
.280AI
.300RUM
6.5CM
6.5SS
7RM

those are amazing groups. can you tell me your load info for the 264 wm? I have a love hate relationship with them and am currently having mine rebarreled and could use all the expertise I can get from someone who obviously knows what they are doing

 

[J E Custom]

The ejector does not create "false headspace", both the firing pin and ejector with push the case forward by the amount of shoulder bump. The amount of shoulder bump is your head clearance when the cartridge is chambered.

And full length resizing eliminates or minimizes the effects of a warped case.

Reloading: Partial Neck Sizing
by German A. Salazar
http://riflemansjournal.blogspot.com/2010/06/reloading-partial-neck-sizing.html

"Now the last scenario, a full-length sized case in which the neck is also fully sized. There is clearance at the neck and in the body of the case, the closest fit anywhere is the bullet in the throat. If the neck to bullet concentricity is good (although it needn't be perfect), then the bullet will find good alignment in the throat and the case body and neck will have minimal influence. Let's not forget that the base of the case is supported by the bolt face or the extractor to a certain degree as well; this is yet another influence on alignment. As you can see, there are several points from base to bullet that can have an effect. My procedure is to minimize the influence of those that I can control, namely the case body and neck, and let the alignment be dictated by the fit of the bullet in the throat and to some extent by the bolt's support of the base. Barring a seriously out of square case head, I don't think the bolt can have a negative effect on alignment, only a slightly positive effect from minimizing "case droop" in the chamber. Given that a resized case will usually have a maximum of 0.001" diametrical clearance at the web, this isn't much of a factor anyway."

When reading the posts here you must distinguish from the die hard neck sizing only reloaders from those who full length resize.


STOP NECK SIZING YOUR BRASS!!!!
By Erik Cortina Team Lapua USA



Below click on image to enlarge.

I'm not going to get into another heated debate over something that has been covered many times. I build custom rifles and anything pushing on the cartridge during chambering and head spacing does have an effect on the accuracy of the head space. That's why all good gunsmiths remove the ejector and the firing when head spacing. I also don't rely on my dies to set head space, I rely on a head space gauge. Proper head space is decided before the first load is developed. Then the re loader can set the ammo up to what ever space he wants to

I do what works best for me and others can do what is best for them.
I don't full length size, Others do. I don't seat the bullets against the lands because I don't have to because I don't load banana shaped ammo and I like the extra velocity without the extra pressure.

I have never told anyone that they must do anything and that everything else is wrong. I only tell people what works for me and they can do what they want with the information. I really don't care what some "Expert" says Unless it works when I try It. I believe in testing all of these theorizes before I adopt them as my regular procedure. Each shooter has his own style of shooting and accuracy requirements and his own way of loading ammo so who am I to tell him that he is doing it all wrong. With almost 60 years of loading ammo and trying every method known to man I know what works for me in particular uses and rifles and don't get hung up on one method because every rifle and use requires many different methods to get the most out of the rifle and ammo, Not to mention the shooter.

I also competed for many years and soon learned that many if not all of these experts have there secrets and will tell there competition something other than what they actually do to minimize the competition.

Just thought I would explain why I don't believe anything I hear until I try/test it. And all the "Experts" in the world cant force me to do something that is detrimental to my goals of doing the best for my needs

J E CUSTOM

 

[bigedp51]

I'm not going to get into another heated debate over something that has been covered many times. I build custom rifles and anything pushing on the cartridge during chambering and head spacing does have an effect on the accuracy of the head space.
J E CUSTOM

Bumping the shoulder back several thousandths improves accuracy. This is because if the case warps on the first firing the base of the case will be tilted and tilt the bullet in the throat with a neck sized case. The head clearance when bumping the case shoulder back prevents the base of the case from touching the bolt face and tilting the cartridge when chambered.

So again, full length resizing reduces or eliminates any guiding effect the body and base of the case has on the bullet alignment in the throat.

And at the Whidden custom die website they tell you they get the most concentric cases with non-bushing full length dies.

So what good is a warped neck sized case that pushes the bullet out of alignment with the axis of the bore.

The average reloader with a off the shelf factory rifle is better off full length resizing with .001 to .002 shoulder bump on a bolt action rifle. The only rifles I neck size for are my milsurp rifles with over sized chambers to extend case life.

The only part of the full length resized case that touches the chamber walls is the case shoulder.

So go back and read what the competitive national shooters, German Salazar, Erik Cortina and Kevin Thomas have to say about the subject that I posted. Kevin Thomas worked in the Sierra Ballistic test lab and now shoots for Team Lapua USA. Are "YOU" going to say that "YOU" have more experience than these three national shooters.

And stop thinking only your opinion matters in a reloading forum. And go to Benchrest Central and Accurate Shooter and catch up with the rest of the world.

 

[J E Custom]

[QUOTE="bigedp51,

And stop thinking only your opinion matters in a reloading forum. And go to Benchrest Central and Accurate Shooter and catch up with the rest of the world.[/QUOTE]

You are so interested in being argumentative and What everyone else says that you did not even read the post. I said my opinion was just that, MY OPINION And you Don,t apparently have any experience to form your own opinion. You just keep quoting everyone else.

You have lots of pictures and most if not all are wrong, like the primer being used to head space and the fine example of banana shaped loads.
I for one have never seen or loaded banana shaped ammo. Mainly because it wont chamber.

I have said many times that full length sizing was necessary for some applications and neck sizing for other applications. why would I subscribe to both if there were no benefits to apply the one that worked best for the application.

I will try to explain one more time for your benefit, and then I GIVE UP !!

This is a thread about Concentricity right?
The most concentric thing to the barrel bore is a properly chambered chamber.
When a cartridge is fired in this chamber It to becomes concentric.
If the case neck is turned true, Then the outside and the inside of the neck are now concentric to the barrel bore.

When you order a set of custom dies, normally the die maker wants at least 3 cases that have been fired at least 3 times to assure that they are a perfect fit in your chamber.

So now you have a perfectley concentric chamber, and a perfectly concentric case including the shoulder, OD of the neck and ID of the neck and everything is concentric to the barrel bore. all of this has .0000 run out and you have a perfect set of dies based on your perfect
chamber. You should have .000 head space. so everything is perfect (Or as perfect as you can get).

The round will still chamber and you want to full size the case so that It is no longer a perfect fit, and in addition You bump the shoulder even though it did not need to be bumped so that it fits even worse?
I don"t see anything about this process that produces concentric ammo consistently. it does make semi autos function better and with no problems.

So It is my belief, that if you want concentricity in your ammo there are things that can improve the quality of your loads,you should also have concentricity in everything else to achieve concentricity in the first place.

In addition to all of this concentricity of chambers and dies the loader still has the responsibility to load concentric ammo.

DONE

J E CUSTOM

 

[bigedp51]

I will try to explain one more time for your benefit, and then I GIVE UP !!

The last time you said you were going to put me on your ignore list and you didn't.
And you do not have to explain anything to me because you are a condescending know it all.
Do you actually think you are the only one in the world who knows how to reload.
Stick to making muzzle breaks and stop trying to dominate this forum.

P.S. Whidden custom dies doesn't make neck sizing dies, because competitive shooters no longer neck size.

And your vast knowledge is truly amazing.......................

I for one have never seen or loaded banana shaped ammo. Mainly because it wont chamber.

NECO CONCENTRICITY, WALL THICKNESS AND RUNOUT GAUGE
http://www.neconos.com/details.htm

Also referred to as "The Case Gauge," this item is designed to measure:

1) The curved "banana" shape of the cartridge case;
2) The relative wall thickness variation of a cartridge case;
3) The cartridge case head out-of-squareness;
4) Individual Bullets - out-of-round "egg shape" and/or
curved "banana" shape (excepting very small bullets);
5) The seated bullet and cartridge runout of loaded rounds. The accuracy of any firearm is determined -- and limited -- by the quality of the ammunition shot in it. The effect of imperfections in ammunition is cumulative; each flaw adds to the influence of all others. Precision shooters spend much time and effort "uniforming" cartridge cases, using advanced techniques to eliminate variation. Yet until recently, one of the most important of these variations has not been susceptible to detection by any device readily available to marksmen.

Normal manufacturing tolerances cause brass cartridge cases to vary in wall thickness around the circumference of their bodies. Under the stress of firing, a case with such variation stretches more readily along its thin side, transferring more pressure to the bolt face at that point and introducing an unbalanced force which contributes to bolt whip and vibration of the barreled action in its bedding. This whip and vibration varies from one shot to the next as cartridges are fired with their thin sides randomly oriented at different angles, causing reduced accuracy. The problem is made even worse if the brass is too hard or springy to completely fireform to the shape of the chamber, in which event the greater stretching of the case's thin side will cause it to develop a curve along the length of its body. These "banana" cases cannot hold a bullet aligned with and centered in the bore, undercutting the effectiveness of the handloader's careful case preparation.

 

[J E Custom]

I think I will take your advice and try the ignore Feature on you. I have never felt it was necessary before now.

We will see how long you can keep your post civil and interesting.
Don't know what you will do without me to spew your venom at.

Obviously I cant help you, and you sure cant help me without the help of the internet and all of the known experts.

I apologize to the rest of the membership for getting into this mess In the hopes I could present my views and beliefs. but with some there is only one way to do anything and everything else is wrong so they are beyond any reasoning and everything on the internet is true. Believe who you want to, and live with the consequences.

J E CUSTOM

 

[bigedp51]

You have lots of pictures and most if not all are wrong, like the primer being used to head space
J E CUSTOM

When you make a workup load and start at the suggested starting load the primers will back out and protrude from the base of the case. When this happens the case is headspacing on the primer and not the base of the case. Then as the pressure increases enough to push the case against the bolt face the primer will become flush with the base of the case.

With a new unfired case you can start a fired spent primer into the primer pocket and chamber the case and let the bolt face seat the primer. Eject the case and the amount the primer is protruding is your head clearance.

Why can't you grasp simple facts and illustrations and then insult people telling them they are wrong on something you know so little about.

P.S. Put me on your ignore list, that way you won't spend so much time with your foot in your mouth showing your ignorance.

 

[Rich Coyle]

When you make a workup load and start at the suggested starting load the primers will back out and protrude from the base of the case. When this happens the case is headspacing on the primer and not the base of the case. Then as the pressure increases enough to push the case against the bolt face the primer will become flush with the base of the case.

With a new unfired case you can start a fired spent primer into the primer pocket and chamber the case and let the bolt face seat the primer. Eject the case and the amount the primer is protruding is your head clearance.

Why can't you grasp simple facts and illustrations and then insult people telling them they are wrong on something you know so little about.

P.S. Put me on your ignore list, that way you won't spend so much time with your foot in your mouth showing your ignorance.

If you don't mind would you tell us what this has to do with concentricity?

 

[bigedp51]

If you don't mind would you tell us what this has to do with concentricity?

Go back and read post 35 and the first two paragraph by J E Custom. He is ranting about a older post and a headspace "discussion" we had. So ask J E Custom why he brought it up in this posting about concentricity.

 

[Reload10]

When you make a workup load and start at the suggested starting load the primers will back out and protrude from the base of the case. When this happens the case is headspacing on the primer and not the base of the case. Then as the pressure increases enough to push the case against the bolt face the primer will become flush with the base of the case.

With a new unfired case you can start a fired spent primer into the primer pocket and chamber the case and let the bolt face seat the primer. Eject the case and the amount the primer is protruding is your head clearance.

Why can't you grasp simple facts and illustrations and then insult people telling them they are wrong on something you know so little about.

P.S. Put me on your ignore list, that way you won't spend so much time with your foot in your mouth showing your ignorance.

Thank you for posting this. This is a great illustration!

 

[rockwind]

Bigedp51,
Thanks for the reply. Right now and for at least the next 5-7 years I will be limited to shooting my factory rifles as I wont be able to afford building a true long range rifle till my boys are out of collage. That's not to say I wont convert one of my rifles to a long range platform, but it the only major change besides optics would be a better stock and glass bed job.

I would also likely upgrade to Norma brass. I would likely buy the Sinclair and Redding gauges you recommend I already have invested in Forster BR dies and Redding body only sizing dies for most of the rifles I reload for and would simply get those 3 dies for the few I don't have them for now.

Thanks,
Arthur.

darton,,, as a somewhat new reloader with a couple custom rifles, i started reloading not to save money, cause i doubted that was the case, but to make better ammo than i could buy.

i can tell you the two most frustrating tools i bought were a borescope and a accuracy one concentricity guage. not because they are not nice tools, but because i was blissfully ignorant before and they constantly show you all this stuff you need to fix,,,and even my expensive redding dies won't produce concentric ammo and then you look at your barrel inside and you go, holy crap, what are all these marks. it can be a frustrating journey, don't give up. i eventually just stopped checking my concentricity but i can say that out of the tools i have, it would be the last tool i would buy if i was doing it over

the best "factory" ammo i personally think you can buy is that AB ammo, applied ballistics,,,i think they sold it to berger so now it is berger ammo. not sure if it is the same quality since berger took it over but when applied ballistics made it, i never saw such low sd and es's out of any other ammo, including the 2 "bigger" custom reloading places,, copper creek and that other one. i have never tried desert tech or gunwerks ammo,, maybe it's good.