Neck "Turning"- the inside, not outside?

[Willie]

Ok so you first need to push variances to outside..
I know it's a crude picture but was thinking along these lines.The thicker parts of the neck are supposed to be inconsistencies (exadurated).

Cheers Rushty

You're getting the gist of it. Push to outside and turn it off. After a time, as FL resizing and trimming will shorten the neck, the shoulder will migrate into the neck. This is where donuts are born. You may have to expand and turn again, in the future.

I'm sure there is a thread here somewhere, that will take you through all the steps. I have always been served well by my K&M tools. Best to find a mentor, to get started.

 

[BoydAllen]

Not that I have the equipment to do it, but there is one method of turning necks that requires a lathe, where a mandrel is turned every time and case necks are forced onto that mandrel and the whole case turns with the mandrel. This is the only method that I am aware of where a constriction can truly be pushed entirely to the outside of the neck and actually be there throughout the turning process. Other methods that have the case neck turning on a stationary mandrel have neck to mandrel fit requirements that preclude cutting off all of the extra thickness...because of spring back.
Here is one example.

Slightly different approach that I like better.

]

 

[Joe R]

Methods of Turning Necks.
On new cases: If the neck inside is concentric with the case body outside, then you could safely outside turn an uneven neck to a uniform neck thickness using current tools and get straight cases. But new cases would most likely not be concentric anywhere so turning new cases is out.
On fired cases: The neck outside would be concentric with the case body, if the chamber is concentric. Then turning the neck inside off the neck outside surface would result in the neck being uniform thickness and now concentric with the case body and also the chamber axis. The bullet would be in the centre of the case and chamber and also aligned with the throat and barrel.

Of course there are some assumptions in the above, but turning the neck inside would seem better than outside IMO.
Are there tools to "turn" inside the neck? (not a reamer)

LC

LC,
I may be dense, but it seems to me your goal is concentric brass, right? Why is concentric brass important to you? I assume your overall goal is better shooting ammo, right?

Concentric brass and ammo is a by-product of a good reloading process, it is not a goal. A common misconception created and propagated by people trying to sell you tools and accessories that serve little or no purpose.

As I learned from Erik Cortina, the Holy Trinity of precision reloading are:

1. Powder - the selection and measurement of it.
2. Seating depth.
3. Neck tension.

Concentricity is not in there anywhere. Concentricity for concentricity sake is a fool's errand. Don't ask me how I know that. It's embarrassing to admit it now. I assume you don't believe me, so read this thread, it will open your eyes.

http://forum.accurateshooter.com/threads/my-new-260-ai-build.3909184/

 

[Richard Coody]

Well i am still in the experimental stage on the benefits of neck turning. I am most interested in consistent neck tension. Seems to me that consistent neck thickness can be beneficial here. Concentricity is an indicator of how well your brass prep and reloading procedures are working. I mostly shoot jams so it is less of a concern for me.

 

[Joe R]

Well i am still in the experimental stage on the benefits of neck turning. I am most interested in consistent neck tension. Seems to me that consistent neck thickness can be beneficial here. Concentricity is an indicator of how well your brass prep and reloading procedures are working. I mostly shoot jams so it is less of a concern for me.

Richard,
You are right as rain. But you already know that.

The only reason I turn necks now is for consistent neck tension. Neck tension was by far the toughest nut to crack for me. Powder was just a matter of buying better scales. Seating depth is so easy is pathetic. But neck tension vexed me for a year before I finally found the solution to it with the help of my gunsmith.

Kindest regards,

Joe

 

[dannyjbiggs]

Richard,
You are right as rain. But you already know that.

The only reason I turn necks now is for consistent neck tension. Neck tension was by far the toughest nut to crack for me. Powder was just a matter of buying better scales. Seating depth is so easy is pathetic. But neck tension vexed me for a year before I finally found the solution to it with the help of my gunsmith.

Kindest regards,

Joe

+ 1, and importantly for chamber neck clearance, too.

Dan

 

[243winxb]

The neck needs to be held by a die while inside neck reaming to a finished diameter.

The old Lee Target Model Loader worked by this process. But a Lee reamed neck is not left with a smooth cut, like outside turning.

 

[Homerange]

The neck needs to be held by a die while inside neck reaming to a finished diameter.
The old Lee Target Model Loader worked by this process. But a Lee reamed neck is not left with a smooth cut, like outside turning.

Correct but there's a major shortcoming with the Lee Target model kit.

As the Lee die/holder is a neck sizing die the neck outer diameter of it needs be close to the same as the neck bore in your chamber. If not the brass will be excessively thinned when inside reamed and the neck to chamber dimensions end up way out of whack.

My dad got a .308 Target model kit 45 years ago and we used it for years, all the time never gaining even decent groups with inside reamed brass. I tried a # of different brands of brass with zero improvement on the piss poor 2 inch groups we always got.
It wasn't till many years later when I got other calibers and a press that I realised there was something grossly wrong with the Lee reaming as all my other loads for different calibers shot so much better. (unreamed and NS)
I got some other unmolested 308 brass and with an OLD FL die set immediately shot under 1 inch without ANY load development. (same rifle)

With matching rifle chamber neck dimensions OR machining the neck in the Lee die to match a rifle chamber neck the Lee system should work fine but to this day I still am saddened by all the 60's LC brass I had to biff out after being reamed to too thinner neck wall thickness.

 

[KenOath]

Richard,
You are right as rain. But you already know that.

The only reason I turn necks now is for consistent neck tension. Neck tension was by far the toughest nut to crack for me. Powder was just a matter of buying better scales. Seating depth is so easy is pathetic. But neck tension vexed me for a year before I finally found the solution to it with the help of my gunsmith.

Kindest regards,

Joe

I use a 21st Century Hydro Press to seat bullets, I batch bullets according to pressure and am able to batch the 50 rnds needed for a match within a couple of PSI from one another.. I'm wondering if turning my necks will give me anymore consistency than I'm currently getting? Only way I will know is to turn necks and test for myself I guess..

Cheers Rushty

 

[Richard Coody]

I use a 21st Century Hydro Press to seat bullets, I batch bullets according to pressure and am able to batch the 50 rnds need for a match all within a couple of PSI from one another.. I'm wondering if turning my necks will give me anymore consistency than I'm currently getting? Only way I will know is to turn necks and test for myself I guess..

Cheers Rushty

That is what i am doing. Just annealed my first experiment. Will size and load them friday and shoot them Saturday morning. Will sort by bearing pressure.

 

[LC Tikka]

Basically my point is: When the thickness variation or error ends up on the inside of the neck as with fired cases, why turn the outside. Also leaving the outside surface of a case original could well be structurally more sound. Where this method helps in obtaining concentric ammo for those working to improve their reloading "great"!
Regardless, at the moment outside turning seems to be the only option for over the counter reloading tools.
Thanks for the interest and input.
LC

 

[Joe R]

Basically my point is: When the thickness variation or error ends up on the inside of the neck as with fired cases, why turn the outside. Also leaving the outside surface of a case original could well be structurally more sound. Where this method helps in obtaining concentric ammo for those working to improve their reloading "great"!
Regardless, at the moment outside turning seems to be the only option for over the counter reloading tools.
Thanks for the interest and input.
LC

LC Tikka,
You're thinking is right on. The outside of the case neck does not matter much when it comes to neck tension, as long as you have .003+ of neck clearance. The only thing that matters is inside diameter. I really got pissed off after K&M ripped me off for $26 for custom mandrels that did not measure anywhere near what I had asked for. So I decided I was going to put an end to this tower of babel where everyone makes mandrels and dies that don't work.

Here's what you're after, I posted this several months ago:

I know that everyone likes to control neck tension with bushings but to me that doesn't seem like a very good way. From my way of thinking bushings transfer any variance in neck thickness to the inside of the neck where they have a direct impact on neck tension. That is not a good thing, because no matter how careful you are turning necks there will be variances, and those variances will impact neck tension.

I believe that the outside of the neck has minimal importance. The only important thing is how thick the necks are because that has an influence on spring-back. IMO the part of the neck everyone should be focusing on is the inside of the neck, or more appropriately inside diameter. The inside diameter is what influences neck tension, if one can transfer neck wall variances to the outside of the case it is that much better.

So the question is how do we control neck tension from the inside of the neck? What if instead of honing die necks (an irreversible and often problematic process because dies are hardened, not to mention that you have to be twice as accurate with a die then with a mandrel, an impossible task) we were to use a mandrel to expand the necks to provide the desired neck tension? What would a mandrel do?

Well, ... a mandrel would control the inside diameter of a case neck much more precisely than any bushing ever can. It could also transfer neck thickness variances to the outside of the neck where it doesn't interfere with neck tension and bullet release. That's good isn't it?

I have been using mandrels for thousands of cases. The problem is that just when I have a mandrel that gives ideal neck tension (down to .0001 precision) it starts to wear, and after a 1,000 cases it is done. Making another mandrel to .0001 precision is very difficult/not possible for most machine shops and grinding shops. It is an expensive trial and error process. So I set out to look for a solution.

Pin gauges are small tubes 2" long and can be bought for a few dollars and they are available in dimensions as exact as .0001 (+/- .00002). They generally have a 60 to 62 Rockwell hardness, like tool steel. They are ideal for this purpose, all you have to do is bevel the tip.

Well, ... to make a long story short Kenny Porter ( kennethp@portersprecisionproducts.com in Lake Jackson, Texas) made this die for me last week. The collet he used is made for lathes so it holds mandrels coaxially straight. This mandrel die makes all other mandrel die I have seen or bought look primitive.

Regards

Joe

 

[dkhunt14]

Basically my point is: When the thickness variation or error ends up on the inside of the neck as with fired cases, why turn the outside. Also leaving the outside surface of a case original could well be structurally more sound. Where this method helps in obtaining concentric ammo for those working to improve their reloading "great"!
Regardless, at the moment outside turning seems to be the only option for over the counter reloading tools.
Thanks for the interest and input.
LC

When you run a mandrel in it pushes the uneven inside to the outside. Like Joe shows. Then when you neck turn it is even. A Reamer or turning the inside is a poor way of doing it. A Reamer follows the hole and it also pushes brass back towards the outside. If you don't have a supporting die it will not get even. It also doesn't make as nice a cut as an outside turn.

With a neck Turner, when you expand to the outside, the expander matches the turning mandrel and the cutting bit on the Turner has the turning mandrel to support it. You can easiky hold .0001 to .0002 accuracy on the wall thickness. It gives way smoother and more accurate cuts. The reason almost nobody makes an inside Turner is because they figured out it just doesn't do an accurate or good job like outside neck turning. Therefore there is no need for it. Matt

 

[.22gongzilla]

Neck turning does not make anything 'concentric'. That's not a purpose of neck turning...

FWIW as a reloader who's never turned necks but always wanted to I'm inclined to agree with this. Concentricity ultimately comes from uniform neck wall thickness so it seems to me it would easier to just turn the outside and then fire-form. Where I get lost is having to use an "expander" die to get new brass snugly onto a pilot.

 

[Richard Coody]

FWIW as a reloader who's never turned necks but always wanted to I'm inclined to agree with this. Concentricity ultimately comes from uniform neck wall thickness so it seems to me it would easier to just turn the outside and then fire-form. Where I get lost is having to use an "expander" die to get new brass snugly onto a pilot.

Just started. It is a piece of cake. Size your brass then use your expandrel mandrel die with the proper expandrel for your neck turner to expand the necks to the proper diameter. Then have at it.

 

[BoydAllen]

A friend has spent a lot of time working with a couple of small calibers, the .17 and .20 Ackley Hornets. He turns necks, but even so has found that he is able to have more precise control of neck tension by incorporating mandrel expanding into his process. He experiments with different mandrels until he gets the exact seating feel that he is looking for, and is rewarded with better accuracy than he was able to achieve by sizing alone. I think that those little cartridges are more sensitive to that sort of variation.

 

[Richard Coody]

A friend has spent a lot of time working with a couple of small calibers, the .17 and .20 Ackley Hornets. He turns necks, but even so has found that he is able to have more precise control of neck tension by incorporating mandrel expanding into his process. He experiments with different mandrels until he gets the exact seating feel that he is looking for, and is rewarded with better accuracy than he was able to achieve by sizing alone. I think that those little cartridges are more sensitive to that sort of variation.

I would much prefer an expandrel mandrel over a bushing die. I just use whiddens full length sizing die with the expander ball kit for adjusting neck tension. Serves much the same purpose

Maybe the pendulum is begining to swing away from bushing dies and all the problems associated with them. The only thing they have going for them is adjustable neck tension.

 

[BoydAllen]

In the past I have been involved in several projects, as the guy that did the measuring and chamber reamer ordering, that started out with a one piece FL die. We measured cases that were sized without the expander assembly, and designed a reamer for a tight neck chamber that would work with that die. The chamber neck diameter was calculated so that with the clearance that we wanted that the die would give the neck tension that we were looking for, with case necks that had been turned to a suitable thickness. Later, I was able to do a variation of this that gave a difference of .001 in neck tension depending on whether the expander was used. Expanding that little does not cause problems. Starting with the die is a better approach because you do not have to guess about brass spring back. One thing that I recommend with this approach is that you use old, much fired and work hardened brass for sizing to determine body dimensions, because it will come out of the sizing die slightly larger than new brass, and if you are cutting your loaded round to chamber clearances to the minimum, the difference could be important. Today, I would probably anneal the necks of the test cases to get a truer reading on the ID of the die neck. I would do this as a separate step from making the body measurements.

Added later: I got so busy telling the story that I forgot to mention its point as it relates to this discussion. I have measured the end of neck runout of cases that were for chambers (tight neck) matched to one piece dies. It has run about .0003 or so.

 

[Joe R]

I would much prefer an expandrel mandrel over a bushing die. I just use whiddens full length sizing die with the expander ball kit for adjusting neck tension. Serves much the same purpose

Maybe the pendulum is begining to swing away from bushing dies and all the problems associated with them. The only thing they have going for them is adjustable neck tension.

Richard,
I agree with you that bushing dies are not as accurate as FL sizing die. They can't be, simply because the bushing is floating in there.

I use a Redding bushing die when I first start on a new caliber, as soon as I have a few pieces of fired brass I ship them off along with the reamer print to John Widden's shop and get me a proper full length die. I always ask Kyle to make the neck 1-2K smaller than my finished round so that the mandrel can do its thing without much pressure. I always anneal before doing any sizing.

Joe

 

[wapiti25]

Inside neck turning is called "boring". I made my own boring tools. I outside turn the necks as Boyd shows. All this is done on my lathe.