Neck Tension ?

[Ralpharama]

How important is neck tension? And how important to it is annealing?

My budget rotary gas fired annealer really isn't especially precise and from time to time the cases stop turning and so aren't accurately annealed.

There seems to be lots of opinions on YouTube, but as my interest in extra long range increases so I realise that i really need to make my ammo as good as it can be.

As far as I can see the only annealer that is super accurate is the AMP, but this is eye wateringly expensive.

Thoughts? 

[Popsbengo]

1 hour ago, Ralpharama said:

How important is neck tension? And how important to it is annealing?

My budget rotary gas fired annealer really isn't especially precise and from time to time the cases stop turning and so aren't accurately annealed.

There seems to be lots of opinions on YouTube, but as my interest in extra long range increases so I realise that i really need to make my ammo as good as it can be.

As far as I can see the only annealer that is super accurate is the AMP, but this is eye wateringly expensive.

Thoughts? 

Consistent neck tension seems to be the issue rather than higher or lower tension settings.  I've experimented with different bushings/mandrel expanders and have settled on .002" under calibre for .308, 6.5CM & .338LM.  Using an in-line bullet seater with an arbour press one can really tell how consistent the necks are.  It's important to ensure the inside of the neck is clean and smooth - lube is a matter of opinion, I use graphite dry-lube on untreated bullets.

A problem with low neck tension is bullet movement in the case due to knocks and also the risk of pulling a bullet out of the case if unloading a live round - powder everywhere...

I have read that gentle taper crimping can work (Andrew from Montana mentioned on here I think?)

I use molten-salt annealing and it's extremely repeatable, much more so than gas flame.  I would expect an induction heater to be excellent too, but it's either make one (loads of advice on line) or save your pennies up!  I used to maintain 60kW RF induction heaters back in the day for RR, bit too much for a brass case 😁

[Re-Pete]

I find the gas fired job sold by "raptor calls" works very well, and appears to give consistent tension, judged subjectively by feeling the resistance when seating bullets.

Annealing also prolongs case life........I bought mine after suffering a spate of split necks. Not had a problem since, and I'm getting 20+ firings from Lapua brass.

And I was told by a successful competitive shooter 9 or 10 years ago that consistent neck tension has more effect on group size than weighing powder to a tenth of a grain......

Pete

[Popsbengo]

1 hour ago, Re-Pete said:

....

And I was told by a successful competitive shooter 9 or 10 years ago that consistent neck tension has more effect on group size than weighing powder to a tenth of a grain......

Pete

I'd agree with that from my own tests so I do both.   My Lapua brass lasts until the primer pockets are too slack, usually 12-15 uses for LRP brass - I run quite hot but not "F Class silly".  Not got to a problem yet with 6.5CM SRP or Lap Mag.

[Pat Allen]

Neck tension is a sensitive topic. My experience with slow burning powders is that more is better. But it’s a case of what works for your rounds is key. I don’t go with anyone’s comments without testing for myself. 

[No i deer]

On 9/24/2023 at 1:01 PM, Ralpharama said:

How important is neck tension? And how important to it is annealing?

My budget rotary gas fired annealer really isn't especially precise and from time to time the cases stop turning and so aren't accurately annealed.

There seems to be lots of opinions on YouTube, but as my interest in extra long range increases so I realise that i really need to make my ammo as good as it can be.

As far as I can see the only annealer that is super accurate is the AMP, but this is eye wateringly expensive.

Thoughts? 

Rob will anneal your brass on his AMP at 10 pence a case

[Ralpharama]

On 11/30/2023 at 7:37 PM, No i deer said:

Rob will anneal your brass on his AMP at 10 pence a case

He's done one lot already 😃 I'll have another pile when he gets back from his world tour 🤣

[Ralpharama]

I am debating whether to buy a bushing die for my .338 or just use a mandrel die after using a regular die? BUshing dies for this caliber seem to be few and far between, even for ready money 🤣 

Any thoughts ?

I'm not going to open up the argument between Neck and Full because the world seems to be split with excellent arguments on both sides. As an engineer, I personally feel that neck sizing has the merit of not work hardening the whole case, only the bit that is regularly annealed.    

[No i deer]

Use your usual die and get a neck tension mandrel 

[Popsbengo]

2 hours ago, Ralpharama said:

I am debating whether to buy a bushing die for my .338 or just use a mandrel die after using a regular die? BUshing dies for this caliber seem to be few and far between, even for ready money 🤣 

Any thoughts ?

I'm not going to open up the argument between Neck and Full because the world seems to be split with excellent arguments on both sides. As an engineer, I personally feel that neck sizing has the merit of not work hardening the whole case, only the bit that is regularly annealed.    

Redding bushing dies are available, and excellent quality.  Just watch out for the case-head swelling near the web, Redding dies aren't particularly 'small base'.  If I need to adjust the case from someone else's once fired brass I use a Hornady die which is pretty tight at the base.  I made a gauge (Big Al's advice) to test at 0.5" up from the head - .338 running 93 gr N570 really work the brass!

On 6.5CM I use a 21stC sizing mandrel to final size as it seems to give a touch better grouping, possibly due to neck tension optimisation (in my custom chambered Barnard Dolphin).  I can hold ~1/4 moa elevation at 1000yds.  Pity my wind reading is less than wonderful 😉

Tried mandrels with .338LM but no benefits realised at my usual >1000 distances.

[SikaJames]

Hi Ralparama,

I pretty much agree with Popsbengo, consistency is key. I defo prefer FLS, as the brass is the same every time , and do use neck bushings because i can control the amount of neck expansion (and I have some neck-turn chambers).   I want to use a bushing small enough, that I plastically deform the neck from the inside. So, I target the expander / mandrel moving the neck about 3-4 thou diameter.

Until recently, I also used a mandrel on the neck, to give me a nominal .002 of neck tension on the bullet.  I recent bought Redding carbide button, and that seems to give same run-out....and saves me a trip through the press.

Annealing does give consistency over repeated firing of the brass.  With a Wilson seating die, I can feel it, but I don't have a force gauge to actually measure it.

I do have an AMP annealer, but I used to flame anneal in a simple tube in a slow rotating drill chuck, and a MAPP gas flame.  I used two temperatures of Temperlac paint to figure out how long I needed in the flame.  I think it was 6 secs for the 300WSM.  Clearly not as gucci, or easy to use as the AMP , but it does work.

A chum of mine has built his own induction annealer, and this is a clever way to go, if the budget it tight.  Or find someone locally, who'll let you use their AMP, for a pay-per-go fee.  

I do feel that with the AMP, I'm also buying a lot of know-how, as they've done a tonne or hardness testing, so their settings should be optimally effective.

 

Good luck on your quest for long range precisison

J