Consistency of neck tension on new and fire led brass

[loud_noise]

hi everyone,

I have been reloading for about 2.5yrs but have started to get more interested in getting consistency in my brass, particularly neck tension.

What are the tools and steps required to maximise the consistency neck tension in both new and used brass? I know this is basic for those experienced and competitive in the benchrest disciplines but I am beginning to appreciate the value of good brass prep for consistent results.

Thanks very much in advance for any advice offered.

 

[DngBat7]

For me, being into this for a short while, skimming necks with neck turning, making them uniform and running a mandrel after sizing makes my necks very consistent.

 

[olddav]

If you don’t want to turn necks focus on trimming brass to consistent length and anneal. What cartridge are you loading for?

 

[JMayo]

Buying good brass that has a reputation ....

 

[rwj]

hi everyone,

I have been reloading for about 2.5yrs but have started to get more interested in getting consistency in my brass, particularly neck tension.

What are the tools and steps required to maximise the consistency neck tension in both new and used brass? I know this is basic for those experienced and competitive in the benchrest disciplines but I am beginning to appreciate the value of good brass prep for consistent results.

Thanks very much in advance for any advice offered.

A good wall thickness micrometer (Mitutoyo 115-313 for one) having a ball end. This will permit you to determine the amount, and extent, of neck wall thickness variation. If you decide to start neck turning, either for chamber clearance and/or to reduce thickness variation, related equipment will be required. Fortunately, there are many good ones to choose from and each has their champions on this forum! A simple forum search will reveal them. More good news is that used ones are often available for sale in the classified section.

Also on the list is annealing. This being a somewhat “emotional” topic for which much info can be obtained via a search. As with neck turning equipment, used annealing equipment is often for sale in the classified section.

Another shooter begins their descent down the rabbit hole! No worries, there’s lots of us waiting for you down here!

 

[mikecr]

With partial neck sizing, necks grip seated bullet bearing by springing back with force against that area. Necks only spring back a max of ~1thou(yours probably less), and the gripping force within this amounts to that provided by the brass hardness X the area it's springing back against.
If you minimally downsize normal & consistent hardness necks to 1thou interference(actual)(1thou under cal), and your neck sizing length is no more than seated bullet bearing (which should be well above donut area), you should have very consistent neck tension. This, regardless of seating forces.
The logic here is that minimal gripping equals minimal variance of it.
Your load needs to be developed with this as a stable precondition.

Annealing softens brass. It reduces spring back forces, and so it reduces neck tension (and variance of it). This can be a good part of load management if the annealing is done right and at a consistent frequency to be stable. But it's also a precondition to load development, and the load needs to like it. If your cartridge/load needs different tension, then the neck sizing length can be adjusted to less or more. FL sizing of necks increases tension, possibly to extremes (binding). It brings donut area, shoulder angle/bumping, and bearing-base binding into neck tension, increasing variance. Higher tension alone increases variance of it. I would never FL size necks. Instead, I would find higher starting pressures through seating into lands (ITL).

Excess downsizing with partial length, FL neck sizing, and extreme sizing do to excess neck clearances, does nothing 'good' towards managing neck tension. IMO, these lead to the most common tension issues people get themselves into.

 

[JimSC]

take a case sized as normal and measure the neck then seat a bullet. Measure the neck a second time. That will tell you how far you stretched the brass. Pull the bullet and remeasure the neck a third time. If the measurement is greater than it was in measurement one then when seating you went past the yield point of the brass and into the plastic deformation range. If that happens you can either anneal or use a larger neck bushing so you are not stretching the neck brass as much. I size .003 under and run no turn chambers with medium hot loads and the primer pockets are always the first part of my brass to fail. But then keep in mind I shoot F class and am not one of the guys shooting in the .1's and zeros

 

[loud_noise]

Thank you to everyone for the detailed responses.

I’m currently shooting .223Rem and .280AI. I have Nosler and Hornady brass for the .280AI and a cheap but surprisingly good Australian brass for (local) for my .223Rem. I’m planning to improve performance through improving the brass prep component of my loading process.

Objective is to reduce ES and consistency in my .280AI velocities as mostly as I am using this as my 900M and beyond rifle.

I have the measuring device for neck thickness that I will start using to measure out the thickness of the brass I’m currently using.

 

[loud_noise]

A good wall thickness micrometer (Mitutoyo 115-313 for one) having a ball end. This will permit you to determine the amount, and extent, of neck wall thickness variation. If you decide to start neck turning, either for chamber clearance and/or to reduce thickness variation, related equipment will be required. Fortunately, there are many good ones to choose from and each has their champions on this forum! A simple forum search will reveal them. More good news is that used ones are often available for sale in the classified section.

Also on the list is annealing. This being a somewhat “emotional” topic for which much info can be obtained via a search. As with neck turning equipment, used annealing equipment is often for sale in the classified section.

Another shooter begins their descent down the rabbit hole! No worries, there’s lots of us waiting for you down here!

Thanks for the advice and yes...I am probably going down a crazy rabbit hole with this.

What are the tools needed for neck turning?

 

[Straightshooter1]

Thanks for the advice and yes...I am probably going down a crazy rabbit hole with this.

What are the tools needed for neck turning?

Something like the following:

https://www.brownells.com/reloading...g-kit-sku749011587-35270-74355.aspx?rrec=true

or

https://www.midwayusa.com/product/1017596030?pid=293609

. . . an appropriate neck expanding mandrel

. . . good to use a cordless power driver/drill, like: https://www.amazon.com/dp/B00PP6JO88/?tag=accuratescom-20

A case chuck/holder: https://www.amazon.com/gp/product/B00162UHEA/?tag=accuratescom-20

A tube or ball micrometer: https://www.amazon.com/dp/B01524DDIO/?tag=accuratescom-20

While using the neck turning tools above is a good way to go, if one would prefer not to hold it by hand, then this: http://www.xxicsi.com/17-338-cal.-neck-turning-lathe.html

 

[rwj]

Thanks for the advice and yes...I am probably going down a crazy rabbit hole with this.

What are the tools needed for neck turning?

I use the 21st Century Tool powered lathe (http://www.xxicsi.com/powered-neck-turning-lathe2.html) for neck turning, ID/OD chamfering, and length trimming. Definitely not the least expensive equipment, but it delivers excellent results!