So...all the sources tell me I should start neck turning.  I mic the brass, and yep, to make it work I should neck turn.  So I get the kit from K&M, figure out how it works, and do it.  But having never done this I'm unfamiliar with what I'm looking at when I see the finished product  Is it weird that it all shaves irregularly, or does it illustrate the point perfectly that it's only shaving the thicker spots which are the very irregularities I'm removing, like ironing a shirt?  Just trying to make sure I'm doing this right.

You should post a picture.

But it sounds about right.

Eta: except for the ironing a shirt analogy. That doesn't really for at all. You're not pressing the high spot down you're cutting them off.

I never turn necks for brass meant for semi-auto rifles. It won't help because the chamber isn't' tight enough to take advantage of it. Ammo that is meant to fired at 600 yards and loaded one at a time directly into the chamber might get a light skim with a neck turning tool.

I use automotive feeler gages to adjust the neck turning tool. If memory serves me well I think I'm using .012" for commercial Winchester brand .308. I never neck turn surplus Lake City because it isn't worth the trouble. I believe .0145" is recommended when turning .308 Lake City.

If I completely remove brass from the entire circumference of the neck then I have it set too deep. I only want to remove the uneven high side.

You have been looking at the wrong sources.

There are some very advanced folks on the forum who have some important advice that is valuable to consider. But don't let us stop you from learning by doing.

For the OP, you are clearly into the transition from average reloading to the exploration of advanced techniques.

The advice to skip neck turning is mainly driven by the concept that semi-auto chambers are not like bolt action benchrest tight neck ones. So for the majority (of sport chambers) the neck turn concept isn't required. For some part of the folks who concern themselves with accuracy work at distances beyond 300 yards, even with sporting or semi-auto chambers, neck turning and annealing might be a benefit or it could be a waste of effort. Much of this answer lies in the balance between your goals and resources.

You can stop reading now, but since you seem to care about this enough to purchase neck turning tools, my guess is you will do your own work anyway. This is not a bad thing as long as you are still getting your bills paid and understand you will conclude as many have before you, that starting with better brass puts you ahead. (Learning to dope wind is more important...)

The use of neck turning is a good technique in your toolbox when you find your favorite brass is hard to get. Variations in material (brands) and nominal thickness can force the issue when you prefer to use a standard die, for example. The insert dies can help with this because they can adjust your process to become the same no matter what the brand of brass is available. (Annealing is more important in the long run, but read on...)

There were articles written in the late 70's and 80's that had us all checking the case wall thickness and clocking the rounds into the chamber even after neck turning was used to get the neck runout down. It made some difference, but it wasn't as beneficial as lets say annealing. Cleary the best outcomes are from brands of brass with the fewest culls.

To find out how much benefit you get from the effort, you are going to need to set up a very carefully constructed test. One set of samples would be your best processing with the worst neck runouts, and another would be your best processing with necks turned from those culls, yet another from the group that didn't need turning cause the runout was low to begin with. You would have to work hard to make sure the only effect being tested is your neck turning, so you may want to read up on load development testing concepts like DOE, Round-Robin, etc.

In many ways, you are at the point in reloading and shooting where you will need to balance limited resources and accepting advice, against the need to explore these advanced techniques to gain your own experience.

I was not born a trust fund baby and had many of the same demands on money and time that most of us do. I had daughters to raise and educate, household and cars that needed work, a wife to keep happy, etc. How much resource you apply to an investigation is up to your specific situation and goals.

In my 20's and 30's, I selected to invest in good tools and ran my own tests. I should add that I was already a trained scientist and was exposed to the world's best ballistics experts due to my day job, but sport shooting wasn't the concern of the DoD back in the Cold War. Competitors and hobbyists have driven many issues to ground for us all to benefit, and in some cases they educated the DoD. The topic you are into is an example of that reverse flow. I often point out well written posts on here to my colleagues and they are amazed at the quality of many of the posts. That said, most experiments have already been run and some beaten to death. Getting your hands on the results is another matter. You are doing this testing to see if you have what it takes to be able to measure the difference, not because the previous posters had it wrong or that you are going to come up with a different conclusion. If you can afford this, you will be better for having put yourself through it.

Read up on the sites that specialize in competition where accuracy at distance is the focus. The F-Class and Precision Rifle competitions have few examples of semi-auto chambering, but still offer well written test reports. High Power events that include rapid strings like Service Rifle are more likely to show the pro's and cons of brass prep techniques in the context of semi-auto loading. The books by Zediker and Litz are also recommended.

When I was at my best, and my equipment and materials were also the best, I could prove the difference in brass quality and case prep and by how much. If your game is up to this, then now is the time in your career to run this to ground. If you stick around long enough, you will see brass shortages and those are not the times to try and run these tests. Do this while time and resources permit.

Good Luck in your journey.

Neck turning is to fit brass to specific chambers and is part of an overall system of reloading.

It's not something that you just do with a SAAMI chamber, and it makes more accuracy.

I've had best results sizing the brass in a full-length die without and expander, and then using a Sinclair expanding mandrel die to qualify the IDs of the necks.

My assumption(possibly wrong), is that the OP is working with a chamber that is .005"+ oversized at the neck(over loaded round diameter) and would be better off just buying Lapua brass for concentricity and save himself a shit load of trouble.


I wonder about all these sources telling him he should be neck turning. Who are these sources and what are they basing this advice on?
Are they fellow bench rest competitors or guys at the local range who spend 2 hours trying to zero their rifles?

Is he currently shooting 1/8th moa with a custom rifle or 1 1/8th moa with a factory 700? Makes a big difference.

Aha, it appears I should clarify a bit for everyone.  I'm shooting a bolt gun, not semi auto, and it's a blueprinted 700 with a 26" Douglas heavy stainless barrel on it.  This is a precision rifle I'll be shooting PRS type matches with.  Strangely it's in .30-06--and there's a story behind that.  I was looking to get a used hunting rifle to yank the action out to build off of but I just happened to find an early 80's long range custom build on the used rack that already had the barrel on it virtually unfired--for $325.  Why burn the savings rebarreling it, right?  Dropped it into an XLR chassis, put a Timney trigger, EGW base, and suppressor on it, and voila, the rifle I wanted just in an unusual (nowadays) caliber for the specific sport.  (And before you go screaming recoil! recoil! recoil! because it's not a 6.5 or 6mm, this thing is HEAVY and has a suppressor on it, so there is very little recoil.)  The chamber is a little tight, sure as heck not oversized.  

The brass I'm using is Greek HXP, which is well made and pretty well regarded among people who shoot match tuned '06 loads.  It is not, however, Lapua or Norma (nor is it priced like them either), so it does have some inconsistencies which the neck turning is desired to remedy. With the neck turning diameter selected I have .0062 total diameter clearance which about matches what German Salazar (PT&G has one of their .30-06 reamers bearing his name, so kind of a big deal) listed in his articles on loading it for his match loads for NRA High Power and F-class.  I followed his advice and mic'd a bunch of cases at 4 points on each neck and recorded the values thereof and then set to turn at a diameter that would be closed to the lowest consistent diameter across the sampling, and arrived at .0126 which was right about at what he had.  

So I'm definitely not in the factory rifle/barrel category.  Dunno if I'm good enough to be shooting 1/8th MOA yet but sure as heck not shooting off the shelf stuff at Walmart either.  And I absolutely do plan on getting an annealing machine, but my wallet needs to recover from all the building and accessorizing of the rifle first.  3 bags, a new optic plus mount, reloading components, bipod, tripod--ouch!

Perfect!

Since you already read German's articles, you are ahead of the game. I really miss his blog.

I would say you just need to make that HXP brass even in terms of neck thickness TIR and compare it to raw HXP to find your answer. Even better if you could sort to a batch of extreme runout samples for an easier contrast. If you end up with loaded bullets that have TIR above 0.003", I am guessing you will see a difference if the turned batch is well below 0.003".

For fun, you will want to compare all of this to raw Lapua. I assumed you have a runout gage.

Do you have a good chrono to check the SD and ES on your loads? Single digit SD helps with the vertical issue once you get out to 600 or more.

I'll have to run out and get one.

Concentricity Gage

Another

and another

Neck Turning by German

Here is an article where TIR didn't make a big difference in commercial 7.62x39 ammo.

TIR versus group size 7.62x39

And the rimfire article where it did make a difference.

Rimfire TIR versus Group

Food for thoughts...

The last time I used HXP ('73, I think) they had donuts. Keep an eye on the neck/shoulder junction.

7.62x39mm ammo has run out? Who'd a thunk it.

The chambers are so huge does it really matter?

Most brass I have ever seen forms donuts after being resized. By setting a neck turning tool to barely skim I usually end up with a complete circumference cut at the neck shoulder junction. I ask my gunsmith for no turn chambers using Lapua brass when having barrels installed. One less thing to deal with.

Go ahead and try it.  If your chamber also takes unturned brass with room to release  the bullet, compare the Results.    What everyone here says or what the internet says is then irrelevant when you've done your own testing.   That was the best advice I ever got from my gunsmith friend when discussing the
Latest trends and magazine articles.

I have turned a few necks, mostly to clean them up/uniform them.  Other reasons such as a tight chamber or oversized cast bullet fitment are valid reasons to do so.

It's not just for tight chambers, it's also for even bullet tension. I neck turn (internal and external) my 7-300WM after sizing my 300WM brass. I did it on a bunch of LC 308 brass too, not sure that was necessary, or I'm that good of a shot to notice any improvement.... 

I think that turning in an ar-15 platform is pointless but in a bolt gun worth while..( I turn my necks for my ar-15 for something to do )
Turning necks is alot of work but as a reloader I find it fun..(I'm a reloading nerd) I think it helps with neck tension. I have a few tight neck bolt guns I have to turn for.. but i have seen improved groups in factory guns as a result of neck turning, and annealing.
Reloading can be very basic, or an art form..it's all up to the reloader..
Just my 2¢