ADJUSTING NECK TENSION

[Bill Norris]

In Cortina's video discussing working up loads, part of the discussion was like this.

REQUIREMENTS FOR WORKING UP ACCURATE LOADS

COMBUSTION - high extreme spread & small group - change powder charge/type, primer, or adjust neck tension.

So, when changing neck tension is he referring to decreasing or increasing it ? That was not clear in the video.

 

[msinc]

Everything I have ever read or seen or heard discussed regarding neck tension is that you want more not less. Tony Boyer, in his book states, "I want as much bullet {neck} tension I can get".
There is a good article in the late "Varmint Hunter" magazine in which the author describes reducing the diameter of the expander ball in your size die to end up with more tension. With bushing dies you simply select a different bushing. In the article he also states what he believes to be the optimal interference fit for different calibers. He says .002"-.003" is ideal for up to like 25 caliber and it gets tighter as the caliber goes up.
I have noticed in checking my dies that Hornady New Dimension dies size necks tighter than the others {of the ball expander types}.

Edit: the guy goes into how annealing and cutting too much off by outside neck turning both work against you by easing up on the neck tension.

 

[Bill Norris]

Everything I have ever read or seen or heard discussed regarding neck tension is that you want more not less. Tony Boyer, in his book states, "I want as much bullet {neck} tension I can get".
There is a good article in the late "Varmint Hunter" magazine in which the author describes reducing the diameter of the expander ball in your size die to end up with more tension. With bushing dies you simply select a different bushing. In the article he also states what he believes to be the optimal interference fit for different calibers. He says .002"-.003" is ideal for up to like 25 caliber and it gets tighter as the caliber goes up.
I have noticed in checking my dies that Hornady New Dimension dies size necks tighter than the others {of the ball expander types}.

Makes perfect sense Bro.

 

[msinc]

Makes perfect sense Bro.

Thank you sir, that's something I am not generally noted for!!!

I found it interesting how much importance Mr. Boyer placed on the need for maximum neck or bullet tension, yet not a single word on how to get it or adjust it. Given the detail levels of everything else in his book I found it strange, almost as if he were giving up some well guarded secret that he couldn't ignore for the books sake.
Then again, his hands might have been tied in a manner of speaking...he had the outside neck diameter to match to the chamber and so he couldn't just make the neck as small as it really needed to be.

 

[JEFFPPC]

Thank you sir, that's something I am not generally noted for!!!

I found it interesting how much importance Mr. Boyer placed on the need for maximum neck or bullet tension, yet not a single word on how to get it or adjust it. Given the detail levels of everything else in his book I found it strange, almost as if he were giving up some well guarded secret that he couldn't ignore for the books sake.
Then again, his hands might have been tied in a manner of speaking...he had the outside neck diameter to match to the chamber and so he couldn't just make the neck as small as it really needed to be.

Keep in mind Tony is a short range 6PPC guy. Number 1 powder VV133. It likes neck tension. I quickly learned moving into mid and long range with longer heavier bullets I have better results with minimal neck tension.

 

[Tokay444]

Like with everything else reloading it seems, it’s on a per case basis. Whatever works for a given barrel. Certain loads/barrels/cartridges may like more tension, others may like less. Half the fun is in testing it ‘till you find what works, and then trying to remember what it was you did to get it right.

 

[Bill Norris]

Like with everything else reloading it seems, it’s on a per case basis. Whatever works for a given barrel. Certain loads/barrels/cartridges may like more tension, others may like less. Half the fun is in testing it ‘till you find what works, and then trying to remember what it was you did to get it right.

AMEN to that Bro.

 

[Tokay444]

I’m still trying to remember what I did here...

 

[Tokay444]

Maybe I’ll remember to use the target for what it’s meant for, and write it down next time.

 

[Northridge]

I would suggest trying both lighter & heavier unless your all ready on the light side and really can only go up, let the target decide not conversation. larger calibers say .284 .308 .338 etc. will often survive or handle very well with less static neck tension. good luck

Shawn Williams

 

[PopCharlie]

I shot my 6.5x47L this past weekend. I shot rounds that I had preped my old way (using a polished expander ball to set the tension). I got the usual results...mediocre at best (.5 to .75 inch groups at 100 yards). I also shot 20 rounds I prepped by using my FL sizer with the ball removed. Then setting tension using a Porter die with a .2625 pin installed. This gives me .0015 of interference fit. I had been shooting about .0005. What a difference. After 5 warm up shots out of a cold, freshly cleaned barrel, I shot 3 consecutive 5 shot groups that were about .3 at 100 yards. Small sample, but encouraging. In this case, more tension improved my groups. Based on this, using a mandrel or pin may also create more consistent tension than an expander ball, IMHO.
PopCharlie

 

[msinc]

Keep in mind Tony is a short range 6PPC guy. Number 1 powder VV133. It likes neck tension. I quickly learned moving into mid and long range with longer heavier bullets I have better results with minimal neck tension.

Interesting...I have just started to experiment with this whole neck tension thing. So it's not slow burning powder that likes a lot of tension???? What would you say is the main thing affecting accuracy and neck tension?? Different powders, heavy vs. light bullets???

 

[Homerange]

I’m still trying to remember what I did here...
View attachment 1236896

Got onto shooting a group instead of spotting where each shot lands ?

See that a lot here with novices checking their rifles before hunting trips and they just gotta look for each hole like it's magic or something.

 

[JEFFPPC]

Interesting...I have just started to experiment with this whole neck tension thing. So it's not slow burning powder that likes a lot of tension???? What would you say is the main thing affecting accuracy and neck tension?? Different powders, heavy vs. light bullets???

Turned necks and annealing. I know, no turn is the current fad. Why? No work required. Occasionally it might work but I think odds are against that.

 

[marchboom]

Consistency of bullet tension is critical in maintaining accuracy and low ES/SD. It appears that it's easier to maintain this bullet tension CONSISTENTLY if it's .002"-.003"+ as opposed to a very light tension.

 

[Bill Norris]

Consistency of bullet tension is critical in maintaining accuracy and low ES/SD. It appears that it's easier to maintain this bullet tension CONSISTENTLY if it's .002"-.003"+ as opposed to a very light tension.

T his is what I have seen as well.

 

[mikecr]

I'm sure that with anything beyond underbores(like 6PPC), tension consistency is a bigger hit than amount.
I size ~1/2 neck length for 1thou interference to begin. After load development, I tweak sizing length (my tension adjustment).
In this range, with my chambers, neck sizing is minimal, so tension change is minimal for many reloads.

A competitive underbore rewards high starting pressure, providing for extreme competitive pressures well beyond viable for hunting capacity cartridges. This takes their load into diminished returns, which also equals diminished variance of returns.
Useful when cases only last a handful of shots, and at the same time causing that. A circle, similar to the FL sizing circle.

 

[D-4297]

And SOOOooooo many records ; and wins have been recorded by "F"-class TR shooters setting their rounds up with .0005 interference fit , using 185's , 200's , 200.20x , 215's ... Makes ya wonder how they do it . The "MAGIC" is to make the tension fit the bullet , barrel , load and distance . One size for all ..... fits nobody . What may work for a 6.5 x 47 won't necessarily work for a 284 , or 7mm SAUM . There is no set RULE for neck tension . Just guidelines to work from . Pick a starting point , and work from that . In both directions , if need be .

 

[Triple BB]

Surprised no one is talking mandrels given the topic...

 

[jackieschmidt]

Keep in mind Tony is a short range 6PPC guy. Number 1 powder VV133. It likes neck tension. I quickly learned moving into mid and long range with longer heavier bullets I have better results with minimal neck tension.

I don’t think Tony ever shot a 30BR either.
In my 30BR with 4198, I use as light of neck tension as I can get away with And still keep the bulletis from falling out.

Howerver, I know fellow shooters who use in the neighborhood of .003.