What does turning necks accomplish?

[gamestalker]

You would think a long time seasoned reloader such as myself would know why, but I honestly don't. But the reason I'm asking is, for many years I've seen inconsistencies as to where the brass seals when the round is discharged. This isn't something that is specific to one cartridge or firearm, and is also something I've seen on factory ammunition necks after firing as well.

An example of what it is I see is the carbon residue will produce an obvious ring on the brass where the brass sealed. This ring never appears below the neck, but in some instances, especially with newer brass, the seal will be at the base of the neck where it meets the shoulder. And with softer brass like Rem. the seal will often present right at the mouth after the first couple reloadings. I don't even know if this is something related to inconsistentcies of necks, but I imagine it could.

I'm pretty maticulous about brass preparation. I'm careful about getting head space to as close to zero as possible, I trim to same lengths, ream and chamfer, tumble, and weigh every charge on the RCBS beam scale, but I've never turned my necks. I'm also very maticulous about keeping the chambers on the bolt guns properly cleaned. A friend tried for year to convince me to turn them, but I just never found any reason to justify doing so.

 

[Toml]

I believe it is useful when case necks are sized down to smaller diameters. Because the brass is not uniform in structure it does not compress uniformly, so neck turning evens out the irregular thickness. Haven't done it, but only read about the process.

 

[R.W.Dale]

In a nutshell neck turning lets you use a bushing die w no expander ball to size your necks only the minimum required.

Longer brass life and less bullet runout are the end goals. If you have a really accurate rifle you might see an improvement on target

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[rcmodel]

I had a custom 22-250 years ago that required turning or reaming every so often to allow enough case expansion to release the bullet.

Otherwise neck thickening would eventually start raising pressure.

I also made a lot of 25-06 cases out of GI 30-06 brass and it all needed it too.

rc

 

[higgite]

If a case neck has uneven thickness and is also not concentric with the case body, if I understand neck turning, after you turn the neck it will be the same thickness all around but still may not be concentric with the case body. Will a bushing neck die make the neck concentric with the body and still be the same thickness all around? How about a Bushing type FL sizing die? A Lee mandrel type neck die? Educate me on neck turning and concentricity.

 

[USSR]

There is a lot of false information floating around the net regarding bushing dies. The first is, that you need to turn your necks to be able to use them. This is not the case at all. I shot competitively for 6 years using Redding Competition bushing dies, and never turned a neck. But, to answer the OP, neck turning is typically done for one of two reasons: 1. To reduce brass neck thickness so that cartridges will chamber in a custom tight necked rifle such that are used in benchrest rifles, and 2. To uniform brass neck thickness to promote more uniform neck tension in a rifle with a standard chamber. I have done it for the latter reason, but I can tell you from experience, it won't turn mediocre brass into great brass. Just MHO.

Don

 

[R.W.Dale]

You can certainly load and shoot ammunition loaded on bushing dies w-out neck turning.

Normal dies and the Lee collet push neck thickness variations to the outside of the neck. This still allows for acceptable bullet runout.

Bushing dies however push these thickness variations to the inside of the neck. This can have a very adverse effect on bullet runout. Obviously if you care enough about this sort of thing to bother with bushing dies you probably care enough to get the most out of that die and that means neck turning.

Otherwize the easy thong to do is to sort brass by weight, use a Lee collet die and shoot some groups in the .3"s if you and the gun are up to it.

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[gamestalker]

Thanks a bunch for all the responses, I now have a clear understanding of why this would be a consideration for some. And now that I better understand, I can see it is nothing I'll probably ever need to do. I shoot mostly production rifles anyway, and they all group around a 1/2" or so, which is plenty accurate for me needs.
GS

 

[Walkalong]

rcmodel & USSR pretty much covered it.

It is necessary for custom tight necked chambers.

It may be needed when forming brass from a larger caliber like 30.06 to .270, or .308 to .243. Depends on the chamber.

It is thought to help accuracy by giving more uniform neck tension, and helping to get the bullet more centered, but there is so much involved in that, just neck turning isn't going to guarantee it.

 

[R.W.Dale]

Thanks a bunch for all the responses, I now have a clear understanding of why this would be a consideration for some. And now that I better understand, I can see it is nothing I'll probably ever need to do. I shoot mostly production rifles anyway, and they all group around a 1/2" or so, which is plenty accurate for me needs.
GS

In that case I certainly wouldn't bother.

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[Edarnold]

Neck-turning

One thing neck-turning will quickly show you is how crude typical factory brass is. I had a local gunsmith put together a .243 Winchester target gun for me; he cut the chamber to Match dimensions, and at least a third of the factory-loaded ammunition I had accumulated for another rifle in the caliber would not chamber. Had the same problem with sized once-fired cases from the other gun, so I set up my Forster trimmer with their neck-turning attachment. I set the cut for the minimum that would ensure free chambering. The disturbing part was seeing how lumpy the necks were: most of the cases had metal removed from only one side of the neck, on some there would be a thick area only part of the length of the neck. Obviously the operations involved in taking the full body diameter of the case down to the neck dimensions multiplied any wall thickness differences in the drawn case blank.

As I shoot these cases I will have to be careful to check for more metal migration, the .243 has a reputation for neck thickening issues. Anyway, this explained to me why Lapua makes a big deal about the concentricity of their brass, and the astronomic prices they charge for it.

 

[quartermaster]

Gamestalker, if you are getting 1/2" groups out of your factory rifles, I doubt very much that turning necks would gain you much more.

I have a rifle with a tight chamber which requires me to turn. For the last year, I have been doing it with all my cases. Last summer I had a friend that gave me 15 boxes of once fired Hornady .204 brass. I spent the better part of a weekend this winter doing those. As mentioned above, I use bushing dies and am a believer that even neck tension and bullet release probably helps to gain a bit more accuracy.

I get rediculous when it comes to brass prep. I buy 100 brass at a time and check the neck thickness of each one. If the deviation is more than .0015, I set them aside after turning for foul shots and loading experimentaion, such as setting up for neck turning or neck bushings, and bullet seating. The rest I turn. It is not too bad of a job once you get set up and if you have a decent tool and a good compact drill and batteries and lots of lube. Patience is also required. If I had to do it without a power driver, I probably wouldn't do it. I used to hate to chamfer and deburr until I got my case prep center.

Who knows and who will ever be able to tell if it helps. IMO, it does. I thoroughly enjoy the whole reloading experience. It's kind of a labor of love for me, even the tedious jobs. When I'm on my bench shooting, I always feel better knowing that I have done all I could have for consistancy in my ammo.

I will also admit that I used to be able to turn out some very accurate stuff using my old 2 die sets also, without going through all the work I do now. Too much information on the internet creates more work. If the word, concentricity was never spoken or written, I would still be using my old dies and have enough extra money to have a couple of rifles made

It's all fun!

 

[BigBob3006]

gamestalker,

Turning the outside of case necks corrects an all to common problem of case necks varying in thickness which results in the bullet not being aligned with the bore. This often results in unexplained fliers. I've measured cases that the necks vary as much as .005". The worst example I've run across was in Winchester .22-250. By turning the necks I had a very nice 500 yard prairie dog rifle.

 

[smokey262]

Too much information on the internet creates more work.

Isn't that the truth

I turn necks and anneal plus a few other prep steps for a few rifles, and I do like the consistency that it produces. It also gives me something to do in the winter.

 

[FROGO207]

I investigated this topic years ago. In my research I decided that the factory rifles that I had at the time could shoot as well or better than I was capable of and neck turning would be a waste of time. I still have no match rifles and still do not bother with neck turning even though I know that doing so would improve accuracy just like weighing and headstamp sorting my brass would gain improvements. Not worth the time expended for the small gains with a stock rifle IMHO. I guess it all depends on what you need to get out of your ammo/rifle and how much time you are willing to invest to get there.

 

[243winxb]

Turn for consistency. Turned neck can be used with standard dies, if your cut is not to heavy.

 

[bbuddtec]

For what I've seen, turning necks is for custom benchrest chambers. In particular, to make the cartridge fit was the only reason, as I understand.

 

[helotaxi]

Realize that you can quickly render a standard set of dies useless by overdoing it with a neck turning tool. Get the neck too thin and an standard die can't squeeze it down enough to create any neck tension at all. If you mess up in that regard, you have 3 options, scrap the brass, get a Lee collet neck die or invest in a bushing die and find the proper bushing to give you the correct neck tension. The problem that you will probably quickly run into at that point is that the neck is going to be getting worked a lot with each firing and will end up splitting much sooner that it would otherwise. The moral of the story is to turn the minimum amount needed to achieve the desired result and experiment on a small batch of brass to determine if it's even worth the trouble to begin with.

 

[Skyshot]

I used to turn the necks on 7-08 cases made from 308 brass back before there was much availible commercial 7-08 brass. I still do turn .222 and .243 necks mainly just for concentricity. I just skin off the thick side of the neck though and try not to take off much. I can't say that it improved accuracy though. Maybe in the.222 as it had a pretty tight throat, but the gains where minimal for me.

 

[joneb]

but I can tell you from experience, it won't turn mediocre brass into great brass.

If there is a variation in neck thickness, it is likely this thickness variation will be in the shoulder and case body.

 

[Walkalong]

Yep, top to bottom.

 

[helotaxi]

But since the neck is the only part that actually contacts the bullet, the variances in the case body are of essentially zero consequence. Firing or sizing the case pushes all the irregularities to the inside so concentricity isn't affected.

 

[Walkalong]

I disagree.

 

[USSR]

I disagree as well. Cases with variances in body wall thickness stretch easier on the side of the case with the thinner body wall, and transfer more pressure back to the bolt face on that side, causing vibration variances that cause reduced accuracy. I took some Lake City M72 Match brass, segregated it by weight and completely match prepped it including neck turning, and I could never get it to shoot as well as out-of-the-box Lapua brass with identical loads (both weigh about the same and produce the same velocity).

Don

 

[RedHeadHunter]

If you are forming your cases, neck turning is almost always a good idea. As for using factory brass in a factory chamber, you may neck turn if you want to "play" with the load to see what it can do. When you turn cases like this, you should not be pulling brass from the entire neck. Adjust the cutter until is just trims the high spots and lumps in the neck. You would be amazed at how uneven the neck thickness on most brass is. I credit this for solving those single irritating flyers in an otherwise terrific group.