Turning Case Necks

[WARFAB]

I did a quick search and didn't see anything on this topic. How many people here do it? I've been considering trying it to see if it makes a difference in my match ammunition, so I read this article entitled "Neck Turning Basics" on 6mmbr.com. If that's just the "basics" then I'm wondering how bad I want to try doing this.

http://www.6mmbr.com/neckturningbasics.html

So who's got experience turning necks? How much difference does it make in group size?

[thughes]

cue Mek in 3....2...1....

[Meketrefe]

Wow another thread about shooting sports! we are on fire!

I do it all the time. Sometimes it is a necessity after necking down brass like creating a wildcat or making 260 brass from 308w for example.

Also in terms of accuracy it does makes a difference. Conventional cartriges with shallow shoulder angles like the 308, 223, 260 etc.. tends to work itself up into the neck area creating uneven
neck tension when seating the bullets so at some point in the brass life or the first time after sizing it is a good idea to turn the necks and have a cutter that can cut a bit into the shoulder but in an angle never straight. Not all the cutters offer this capability so one has to choose depending on what one wants to do.

Consistent brass preparation is very important and 1/2 of the job in the accuracy formulas.

[usmcveteran]

Neck turning is different then trimming?

[WARFAB]

Turning is basically using a mini lathe to make sure that the thickness of the brass in the neck of a case is consistent both around the circumference of the individual case, and for all the cases in a group. I guess the idea is to achieve consistent neck tension on the bullet, which is supposed to enhance accuracy.

No idea how fussy one needs to get to achieve some performance gains. The description of the process in the 6mmbr article seems fussier than I was hoping to get. I was hoping I could just get the basics and turn some cases. No idea if all the special measuring tools are necessary.

I'm also a little nervous about getting lube inside the neck of the case. I've heard that moly coated bullets can be an issue in auto loaders because they might slide forward into the lands when the round is chambered. I figure adding lube to the inside of the neck could cause similar issues so then I'd have to be sure to get everything nice and clean after turning. Trying to find a balance between my OCD and time limitations for doing something like this.

Meke- do you chamfer the cases before or after turning the necks?

[Meketrefe]

I do always run a chamfer and deburr very little just so slightly.
The cutter is just like a little lathe with the exception that it uses a pilot that supports the case and controls the thickness too.
Forster makes great stuff but there are others depending if you want to cut into the shoulder a little or not.
The BR forum is great but some guys there they over do it. I think one can use all soft of micrometers but for the average guy
and specially shooting an autoloaders a few measuraments w/o going too crazy and just to ensure you are within the tolerances
+/- 1-2 thounsands.

There is a guy in youtube that has good videos I think it is called amo-smith or ammosmith or something like that. I sent a few
those to folks who were starting and they said they helped. I don't think it is high end but it explains some basic concepts with
very nice close up footage that is what you want.

Let me see if I find it.

Here enjoy this... 3 part video.

https://www.youtube.com/watch?v=wZBykXq1sSQ

[WARFAB]

I read that you need to cut into the shoulder a bit otherwise the case starts to form a doughnut. (Donut. Doughnut. However you spell it in this instance.)

Is it possible to see improvement just by turning a set of cases the minimum necessary to get a cut all the way around the circumference on all of them? So basically just using the neck turning tool to make sure everything is uniform without actually having to buy a neck thickness gauge.

[Meketrefe]

I read that you need to cut into the shoulder a bit otherwise the case starts to form a doughnut. (Donut. Doughnut. However you spell it in this instance.)

Is it possible to see improvement just by turning a set of cases the minimum necessary to get a cut all the way around the circumference on all of them? So basically just using the neck turning tool to make sure everything is uniform without actually having to buy a neck thickness gauge.

You don't need a neck thickness gauge. Just take several good measures with the calipers tip and take the average.
You can also use a regular micrometer with the pilot in. take a reading on diameter and substract the pilot diameter.
Then divide by 2 and that is the thickness.

You do not cut into the shoulder unless you have an angled cutter. The cutter will have the tipical tip of contact but then
one side that touches the shoulder with the same angle of the shoulder so it will remove on the shoulder side otherwise
you might start cutting into the shoulder and literally cutting off the neck from the shoulder. I mean if you run 1 thousand
over is not going to matter but a bit more and you are compromising the brass.

I have created a simple ilustration for you. I hope this helps.

Here an example of the 21st century cutter. See how the cutter cuts so slightly on the shoulder but with the same angle w/o digging into it. Here someone that might have gone too far cutting into the shoulder with a straight cutter...

[WARFAB]

The only turning tools I've been looking at have angled cutters for running into the shoulder. Haven't gotten too far into the research yet, but had just assumed I'd get one with an angled cutter. Thanks for the illustration. Very helpful.

[Meketrefe]

The only turning tools I've been looking at have angled cutters for running into the shoulder. Haven't gotten too far into the research yet, but had just assumed I'd get one with an angled cutter. Thanks for the illustration. Very helpful.

NP.

Remember, not only an angled cutter but one that matches the angle of your cases or one that can be adjusted. the 21st century is sweet.
Again a straight cut is fine too but one needs to find out where to stop.
A bushing from a neck die could be used as a template for setting up consistent thickness when adjusting the turning tool from one caliber to another.
In most neck turning jobs there is little cutting unless you are necking down a lot. So it is more to make things uniform and eliminate the donut as you call it.