6 BR Neck Tension ?

[Tim Singleton]

New to the 6br. Looking for in put on neck tension. I'm shooting a Savage with a no turn McGowen 28" 1-8 twist bull barrel. In a laminare stock. I put the rig together myself. Usually shoots 3s 5 shots. Currently running the 100 gr Berger bt over 30 gr Varget at 2912 fps low ES. Turned necks on Lapua brass just enough to even out. I'm using Redding neck bushing die with .267 or .268 bushing. The 268 is nearly no tension.

Now the question what do you guys run for neck tension?
I'm beginning to think the least amount is best.
Thanks

 

[hogpatrol]

On my .272 neck, I use a .267 bushing and get a .269 loaded round and that works best for my particular rifle.

 

[Killshot]

My Dasher has a .2704" no-turn chamber.
Loaded Blue Box Lapua cases measure .268" and I use a .266" bushing.

I've experimented with more tension but the results weren't good. Which is odd considering that out-of-the-box virgin brasss used for fireforming probably has like .005" tension and the damn things shoot great.

 

[Tim Singleton]

Maybe I should try a little more tension. I have a.266 bushing. I will try it.

I just wondered what the school of thought was for best accuracy.

Like the killshot said new lapua brass has an extreme amount of tension it will cause pressure signs in a hot load

 

[Heavies]

I used very light tension, .001", soft seat 107 SMK s with very good results in a 24" Mcgowen. Tried 95 SMK s. Those liked more tension.
Your load seems to be working fine. Just try it out, it may get better.

 

[GSPV]

I'm using a 269 on no-turn old, gold box, brass. It's working for me.

I've been told that as the brass work hardens, I will lose tension. I'm going to anneal at that point to see if it cures the problem,

Greg J

 

[Leaddog]

Anneal after each firing for neck tension consistency.

 

[Tim Singleton]

Annealing maybe a step I'm missing. .001 tension with the.268 bushing was working well. Now after 4-5 firings there is no grip on the bullet at all.

Will annealing cure this?

 

[boltfluter]

Annealing may help but .001 is very little tension. Your brass may wear enough from sizing to make this happen. I run .002 tension in my 6 BR and it works great. You could try going down .001 in bushing size and be back to where you started. Just my .002. Good luck. ;D ;D

Regards, Paul.

www.boltfluting.com

 

[Cigarcop]

Anneal after each firing for neck tension consistency.

Listen to this man please

 

[bugman]

Somewhere between .001 and .002 neck tension should get you there with most powders used in the 6br. You need to consider two things that haven't been mentioned.

Neck tension is also a function of surface area. The 6br has a long neck with a relatively great amount of surface area....002+ tension in a 6br holds a bullet quite a bit more than the same tension in a short-necked case.

Also, OAL has to be considered. If you are going to run more than .013 jammed, then anything less than .001 tension may not "resist" reseating of the bullet upon bolt closure. You will need to check this out for yourself because that number can change depending on neck thickness, hardening,, etc..

 

[A j shooter]

Thats soft seating . That's what John whidden does for long range . You just thank your jamming .

 

[Tim Singleton]

Thanks to all who shared their opions.

I have been running light neck tension and letting the bullet seat itself.
I didn't realize this was called soft seating.
This had been working pretty well.
I just wanted to know what others were doing.

Thanks again

 

[Leaddog]

Anneal after each firing for neck tension consistency.

Listen to this man please

You are a kind man, Keith.

 

[BoydAllen]

The difference in bullet grip that you see after a few firings is not due to wear, but increased spring back due to the brass being work hardened by repeated sizing and stretching. The easy cure for this is a smaller bushing. I would fire a set of cases in rotation so that they all have the same number of firings. Some powders "Like" more neck tension than others. The best way to sort this stuff out is to load at the range. I know that most shooters resist this, but it really is the fastest, most efficient way. With a chronograph and some wind flags, you will soon have it sorted out. As far as annealing goes, although short range competitors do not generally do this, it is common among the long range bunch, and may help your results. The problem is that there is more bad information out there than good about how to anneal cases. You do not want cases fully annealed so that their necks are soft. If you search this site, you should come across the best article that I have ever seen on the subject. I suggest that you read it more than once.

 

[CoverDog]

I believe this is the article BoydAllen was talking about.

http://www.accurateshooter.com/technical-articles/annealing/

 

[Bradley Walker]

The article starts out "the world record holder anneals every time", implying that is was some sort of requirement... but then how many world records were set WITHOUT annealing?

The article reads like a commercial for annealers, frankly...

 

[WyleWD]

Totally agree with Boyd's post.

Personally, I like to use "sturdy" neck tension for a couple reasons.

1). If you use little or no neck tension... how do you know that the bullet doesn't hit something on its way to the chamber and get shortened?? Most would agree that seating depth is important for consistent accuracy or we wouldn't spend so much time discussing it or chasing it around, so why take a chance that the bullet gets seated further back than desired during the chambering process?

2) If you have ever had a real low neck tension, then had to pull a round out of the chamber during competition and dumped powder in the action.... that mess will take your mind off what you're doing in a big hurry. Done it once and will never do that again. Trust me.

If you can build your load around using a neck tension that will hold the bullet where you want it, and get away from percieved need for annealing after each and every firing (which I categoricly disagree with) it makes things a lot more simple and fewer things to go wrong. JMHO. WD

 

[Tim Singleton]

Lots of very good in put. Thanks to everyone for taking the time to post what works for them. It s great to have a place to ask questions and learn