Neck Tension vs Bullet Seating & Release Pressure - Lessons Learned

[lyle2231]

That's a lot of good work there, but also, there is a flaw in your foundation.
Bullets are not pushed out of necks (with pull force), but are released from neck grip (by expansion).
So a load could care less about seating force (friction), if tension is still managed to load development.
This muddles up some of your result notions.
On the other hand, you are observing spring back. You can see where excess just hits a wall.

If you really want to adjust tension, you need to vary sizing LENGTH.
This because tension (neck grip) is in PSI. So adjusting area of the spring back grip (force applied) adjusts tension.

Even with well normalized neck friction, tension does not directly correlate with friction (or seating force to overcome it).
And we currently have NO WAY to measure the hoop tension that is neck tension.
In summary, neck tension is neither interference fit, nor friction.

Would it be fair to say that the degree of friction is a by product of neck friction As a result of resizing?

 

[Mikecr]

Would it be fair to say that the degree of friction is a by product of neck friction As a result of resizing?

Not the degree, but a degree, and more or less.
We only need to understand that it's not a direct correlation, and why.

 

[Trangieboy]

The pressure that is expanding the neck to allow bullet release is also pushing on the base of the bullet at the same time.

 

[cohunt]

What is interesting to me about all this is not long ago we had a well known/very respected member here give his opinion on neck tension in another thread --- he said that if he had to pick a number of what neck tension was generally the best/most accurate, and a good number to shoot for to start at--- he would pick 5 thou.

 

[Dirtrax]

What is interesting to me about all this is not long ago we had a well known/very respected member here give his opinion on neck tension in another thread --- he said that if he had to pick a number of what neck tension was generally the best/most accurate, and a good number to shoot for to start at--- he would pick 5 thou.

AW is my guess. I am a fan because he backs up his techniques with down range performance on the record. That's not to say say investigations such as those currently coming forth aren't informative and interesting. I think we'd all like to know why we should implement a practice but in the meantime hits on the target still rule.

 

[ButterBean]

I guess one wouldn't chamfer much using a FCD, right?

Always chamfer

 

[Mike Matteson]

AW is my guess. I am a fan because he backs up his techniques with down range performance on the record. That's not to say say investigations such as those currently coming forth aren't informative and interesting. I think we'd all like to know why we should implement a practice but in the meantime hits on the target still rule.

What is interesting to me about all this is not long ago we had a well known/very respected member here give his opinion on neck tension in another thread --- he said that if he had to pick a number of what neck tension was generally the best/most accurate, and a good number to shoot for to start at--- he would pick 5 thou.

Suggesting 5 thou tension as a good number. My understanding that some testing as to what tension works best in your rifle.

The other is I would think that a crimping die would change the tension that somewhat. Creating more tension. In reading here, the grouping tigthen up more. Just how much I don't know.
In reading the neck should be 1 caliber length of bearing surface. By holding to that amount of bearing surface creating tension it's in away reduced the tension at the same time compaired to the full length of the neck. I was reducing the amount doing this a long time ago it improved my grouping, and have stayed with that by using neck sizing dies only. Setting the length of the neck being sized. That was mostly belted mag cases. At that time I used standard RCBS neck sizing dies. I didn't have clue why. I felt at the time that the alinement of the neck not being size all the way to the shoulder held the case in place better. My groups were better. I didn't try much else.
Now that's a different story. I have been changing out my reloading equipment a ($$$) huge amount over the last plus year
This is not the place to come to, without going down the rabbit hole. . I have to laugh at myself. It's been enlighting, changing my ways and others it just reinforced it.
"GREAT DISCISSION"

 

[Dirtrax]

How is it possible that given the variables in equipment, environment, and rifle/shooter interface can there be any answer. If someone solves it for their rifle odds are it won't work in another. Not yet anyway. Again, the quest is it's own reward.

 

[Mikecr]

If someone solves it for their rifle odds are it won't work in another.

You're right. It is absurd to broadly declare any solution..
Let's say that you could directly measure your neck's hoop tension. With this validation, predictable tension could be defined per alloy, thickness, cal, sizing cycle and annealing scheme.
With sound prediction or actual measure, you could then test to define it's affect to early powder burn, per case volume, case design, clearances, chamber support, bullet weight, and powder attributes.
With that integrated into QuickLoad, some day somebody might be able to predict a best tension setting for a specific set of conditions.

Assuming none of this will happen,, that we will not evolve at all(like the last 100yrs),, then we're left with this as a local abstract & solution. Nothing new there.